Polyketone and process for producing the same

ABSTRACT

There is provided a polyketone comprising repeating units, 95-100 mole % of which are 1-oxotrimethylene and having an intrinsic viscosity of 2.5-20 dl/g, wherein the content of Pd element is 0-20 ppm, terminal structures include an alkyl ester group (terminal group A) and an alkyl ketone group (terminal group B), and the equivalent ratio of terminal group A/terminal group B is 0.1-8.0. The polyketone of the present invention can be used in any forms, such as fibers and films, and can be applied to a wide variety of the uses such as clothing, reinforcing materials for rubbers, resins, cements, and optical fibers, electronic materials, battery materials, civil engineering materials, medical materials, daily commodities, fishery materials, and packaging materials.

TECHNICAL FIELD

The present invention relates to a polyketone which is high in molecularweight, can exhibit ultra-high strength when made into fibers, hasexcellent heat stability and chemical resistance, and is excellent instability of quality during long-term storage, processability at hightemperatures and in wet heat, and stability as a dope in inorganic saltsolvents, as well as a method for producing the polyketone.

BACKGROUND ART

Polyketones having a structure in which repeating units derived fromcarbon monoxide and repeating units derived from ethylenicallyunsaturated compounds are substantially alternately connected with eachother are excellent in mechanical properties and thermal properties andhigh in wear resistance, chemical resistance and gas barrier properties,and thus are expected to be used in various fields. For example,polyketones are useful material as resins, fibers and films having highstrength and high heat resistance. Particularly, when a high molecularweight polyketone having an intrinsic viscosity of 2.5 dl/gd or higheris used as a raw material, fibers or films having very high strength andelastic modulus can be obtained. These fibers or films are expected tobe used in the wide variety of applications of constructional materialsand industrial materials, e.g., belts, hoses, rubber reinforcingmaterials such as tire cords, concrete reinforcing materials, etc.

Polyketones mainly composed of repeating units comprising ethylene andcarbon monoxide have a high melting point of 200° C. or higher,nevertheless, they suffer from the problems that thermal modificationssuch as three-dimensional crosslinking occur under heating for a longperiod of time to cause deterioration of molding processability due toloss of flowability, and furthermore mechanical performance and heatresistance performance of the molded products are lowered owing todecrease of the melting point.

As a method for molding a polyketone into fibers or films with highstrength, a wet molding method which comprises molding a polyketonedissolved in an aqueous solution of an inorganic salt, such as zincchloride (e.g. WO99/18143 pamphlet and WO00/09611 pamphlet). However, inthis method, there are problems that long-term heating of a dope inwhich polyketone is dissolved causes thermal modification of thepolyketone which results in the deterioration of flowability andspinnability of the dope and that mechanical properties of the resultingfibers or films are thus deteriorated.

If a polyketone is heated, it undergoes chemical reactions, such asPaal-Knorr reaction to produce a furan ring and the formation ofintramolecular or intermolecular crosslinking due to aldol condensation,resulting in the progress of heat deterioration of the polyketones.These chemical reactions are considerably accelerated by thepolymerization catalyst (palladium (Pd)) remaining in polyketones. Asmeasures against the heat deterioration, techniques of reducing theamount of Pd remaining in polyketones have been proposed (e.g., EuropeanPatent No.285218, U.S. Pat. No.4,855,400 and U.S. Pat. No.4,855,401).The reduction of the amount of Pd remaining in polyketones brings aboutan effect of improving the heat resistance of polyketones. However, thetechniques disclosed in the above publications are methods comprising:subjecting a polyketone obtained by a conventional polymerization methodto a lengthy Pd extraction treatment using a compound, such astriphenylphosphine, triethylamine or1,3-bis{di(2-methoxyphenyl)phosphino}propane. Therefore, these methodscannot be put to industrially practical use, taking into considerationthe costs for washing facilities, and washing and extracting solvents.Furthermore, since heat deterioration of polyketones also occurs due tothe lengthy heat treatment, the heat resistance of the resultingpolyketones is not sufficient, although the Pd content is small.

“Polymer”, 42 (2001) 6283-6287 discloses that a polyketone obtained bypolymerization in acetone solvent is subjected to the extractiontreatment with 2,4-pentanedione to reduce the Pd content to 20 ppm orless, whereby the heat resistance of the polyketone can be improved.Regarding this polyketone, the polymerization activity obtained underthe above conditions is very low because no alcohol is used as apolymerization solvent. Moreover, since the complicated Pd extractiontreatment must be carried out after the polymerization, the methodcannot be industrially employed from the viewpoints of productivity andcost.

WO00/09611 pamphlet shows a polyketone having a Pd content of 5 ppm.However, this polyketone is obtained by effecting the polymerization at80° C. under 5 MPa and then removing Pd in the polymer by solventextraction. The method thus has problems that the polymerization rate isvery low and that lengthy heat treatment is required during the solventextraction.

In order to reduce the Pd content in polyketone without carrying out thelengthy extraction treatment, it is necessary to produce a large amountof polyketone with a small amount of Pd, namely, to carry out apolymerization for a long time with high polymerization activity. Sometechniques are known as polymerization method with high polymerizationactivity. For example, JP-A-1-201333, JP-A-2-115223, and WO00/68296pamphlet and WO01/02463 pamphlet disclose polymerization techniques withthe very high polymerization activity which exceeds 20 kg/g-Pd/hr. Here,the polymerization activity is an index (unit: kg/g-Pd/hr) which showsan amount of polymer produced per unit of time with the use of a unitamount of a catalyst (Pd in the present invention). The greater itsvalue is, the larger the amount of polyketone obtained from a unitamount of Pd is.

However, all the polyketones obtained by the polymerization methods withhigh polymerization activity (20 kg/g-Pd·hr or higher) disclosed in theabove publications have low polymerization degree and the intrinsicviscosity lower than 2.5 dl/g. The techniques are thus insufficient tobe used for fibers or films with high strength.

With reference to the terminal structure of polyketones, studies havebeen carried out on the relation between the kind of polymerizationsolvent and the structure and ratio of the terminals produced. It isknown that the terminal structure of polyketones varies depending on thekind of solvents used for the polymerization. Chem. Rev., 96 (1996),663-681 proposes the following mechanisms (reaction formula I toreaction formula VI) in the polymerization reaction of polyketone inmethanol, which show that an alkyl ester terminal (reaction formulas I,V) and an alkyl ketone terminal (reaction formulas II, VI) are producedin the initiation reactions and termination reactions. In the followingreaction formulae, L₂ denotes a phosphorus bidentate ligand and Poldenotes a molecular chain of polyketone polymer.

(Initiation Reaction)

Reaction Formula I:

Reaction Formula II:

(Growth Reaction)L₂Pd—CO—CH₂CH₂-Pol+C₂H₄→L₂Pd—CH₂CH₂—CO—CH₂CH₂-Pol   Reaction FormulaIII:L₂Pd—CH₂CH₂—CO-Pol+CO→L₂Pd—CO—CH₂CH₂CO-Pol   Reaction Formula IV:(Termination Reaction)L₂Pd—CO—CH₂CH₂-Pol+CH₃OH→L₂PdH⁺+Pol-CO—OCH₃   Reaction Formula V:L₂Pd—CH₂CH₂—CO-Pol+CH₃OH→L₂Pd—OCH₃+Pol-CO—CH₂CH₃   Reaction Formula VI:

Furthermore, JP-A-59-197427 discloses the terminal structures and ratiothereof in the case of using various polymerization solvents with1,3-bis(diphenylphosphino)propane as a phosphorus ligand. For example,it is disclosed that when an alcohol, such as methanol or ethanol, isused, an alkyl ester terminal and an alkyl ketone terminal are produced,when a glycol, such as ethylene glycol, is used, a hydroxyalkyl terminaland an alkyl ketone terminal are produced, and when a non-protonic polarsolvent, such as tetrahydrofuran or acetone, is used, only an alkylketone terminal is produced. The above publication discloses that whenan alkyl ester terminal is produced, the equivalent ratio of alkyl esterterminal (terminal group A)/alkyl ketone terminal (terminal group B) isnot 1/1, but 0.09/1-1.04/1. However, polyketones illustrated in theabove publication are all polymers with low molecular weights and thepublication makes no mention of polyketones with high molecular weightshaving an intrinsic viscosity of 2.5 dl/g or higher. Specifically, thepolyketones having terminal group A and terminal group B that are shownin Examples of the publication have a number-average molecular weight of250-7500. When the intrinsic viscosity is calculated using the formula(intrinsic viscosity=1.0×10⁻⁴×Mw^(0.85)) described in a publication(e.g., JP-A-4-228613) with prioviso that the molecular weightdistribution (Mw/Mn) is 3.3 which is a value of general polymers, theintrinsic viscosity of the polyketones described in the Examples is0.03-0.54 dl/g, and hence the polyketones cannot be expected to exhibithigh mechanical characteristics of high strength and high elasticmodulus.

Moreover, regarding the polyketones disclosed in the publication, thepolymerization activity is very low, and the theoretical Pd content inthe polyketones, which is calculated from the product of polymerizationactivity and polymerization time (catalyst efficiency) is 100 ppm ormore. Thus, the polyketones contain a considerably large amount of Pd.

Regarding the terminal groups of polyketones, studies are conducted onthe polymerization conditions and the structure and ratio of theproduced terminals, nevertheless, regarding the relation between theterminal structure and the characteristics of polyketones, it is merelydisclosed, for example, in JP-A-2-16155 that the characteristics ofpolyketones do not depend on the structure of the terminal groups.Particularly, no disclosure is made as to the control of structure ofterminal group as a means to improve the heat stability of polyketonesin an aqueous solution of a metal salt.

The object to be solved in the present invention is to provide apolyketone that has a high molecular weight, exhibits high mechanicalcharacteristics and excellent heat resistance and chemical resistancewhen molded into the products, such as fibers and films, and can be usedas inexpensive industrial starting materials. Such a polyketone has notbeen obtained by known techniques. The further object to be solved inthe present invention is to provide a method for producing thepolyketone in a highly productive manner with high polymerizationactivity without carrying out complicated steps, such as catalystextraction treatment.

DISCLOSURE OF INVENTION

In order to attain the above objects, the inventors have conducted anintensive research to improve the heat resistance of polyketones bycontrolling the conditions for the production of polyketones with highmolecular weight and high melting point and controlling the structure ofpolyketones, and, as a result, it has been found that the above objectscan be attained by reducing the content of Pd in polyketones and renderthe proportion of the terminal structures of polyketones within aspecific range. Thus, the present invention has been accomplished.

That is, the present invention relates to the following embodiments.

(i) A polyketone comprising repeating units, 95-100 mol % of which are1-oxotrimethylene represented by the formula (1) and having an intrinsicviscosity of 2.5-20 dl/g, wherein the content of Pd element is 0-20 ppmand terminal structures include an alkyl ester group (terminal group A)represented by formula (2) and an alkyl ketone group (terminal group B)represented by formula (3) and the equivalent ratio of terminal groupA/terminal group B is 0.1-8.0:

(wherein R¹ represents a hydrocarbon group of 1-6 carbon atoms and R²represents an organic group of 1-10 carbon atoms).

(ii) A polyketone of (i), wherein the intrinsic viscosity is 4.0-8.0dl/g, the equivalent ratio of terminal group A/terminal group B is0.5-3.0, and the content of Pd element is 0-10 ppm.

(iii) A polyketone of (i) or (ii), wherein the content of carboxylicacid terminal group is 0-10 milli-equivalent/kg.

(iv) A polyketone of any one of (i)-(iii), which has a DSC melting pointTm³ of 230° C. or higher.

(v) A polyketone of any one of (i)-(iv) which has a DSC melting pointTm³ of 240° C. or higher.

(vi) A polyketone of any one of (i)-(v), wherein the terminal group A isa methyl ester group represented by the formula (4), the terminal groupB is an ethyl ketone group represented by the formula (5), and theequivalent ratio of terminal group A/terminal group B is 1.0-8.0:

(vii) A polyketone of any one of (i)-(v), wherein the terminal group Ais an isopropyl ester group represented by the formula (6), the terminalgroup B is an ethyl ketone group represented by the formula (5), and theequivalent ratio of terminal group A/terminal group B is 0.5-2.5.

(viii) A polyketone of any one of (i)-(vii), wherein when the polyketoneis dissolved in hexafluoroisopropanol at a concentration of 0.1 wt % andultraviolet spectrum of the solution is measured in a quarts cell at ascanning speed of 200 nm/min and a data intake interval of 0.5 nm, theminimum value of absorbance observed at a wavelength of 200-250 nm is0.14 or less.

(ix) A polyketone molded product having repeating units, 95-100 mol % ofwhich are 1-oxotrimethylene represented by the formula (1) and having anintrinsic viscosity of 2.5-20 dl/g, wherein the content of Pd element is0-20 ppm and terminal structures include an alkyl ester group (terminalgroup A) represented by the formula (2) and an alkyl ketone group(terminal group B) represented by the formula (3), and the equivalentratio of terminal group A/terminal group B is 0.1-8.0:

(wherein R¹ is a hydrocarbon group of 1-6 carbon atoms and R2 is anorganic group of 1-10 carbon atoms).

(x) A polyketone fiber having repeating units, 95-100 mol % of which are1-oxotrimethylene represented by the formula (1) and having an intrinsicviscosity of 2.5-20 dl/g, wherein the content of Pd element is 0-20 ppmand terminal structures include an alkyl ester group (terminal group A)represented by the formula (2) and an alkyl ketone group (terminal groupB) represented by the formula (3), and the equivalent ratio of terminalgroup A/terminal group B is 0.1-8.0:

(wherein R¹ is a hydrocarbon group of 1-6 carbon atoms and R² is anorganic group of 1-10 carbon atoms).

(xi) A tire cord comprising at least 50 wt % of the polyketone fiber of(x).

(xii) A polyketone article, characterized in that the polyketone moldedproduct of (ix) or the polyketone fiber of (x) is at least partly usedin the article.

(xiii) A polyketone article of (xii) which is a tire, a belt or abuilding material.

(xiv) A fiber-reinforced composite material comprising at least 1 wt %of the polyketone fiber of (x) in the whole fiber.

(xv) A method for producing a polyketone having an intrinsic viscosityof 2.5-20 dl/g by copolymerizing carbon monoxide and an ethylenicallyunsaturated compound, wherein the copolymerization is carried out in thepresence of a metal complex catalyst obtained by reacting the followingcompounds (a)-(c), in the following liquid medium (d), and under thefollowing conditions (e):

-   -   (a) a palladium compound,    -   (b) a bidentate ligand having an atom of Group 15 elements,    -   (c) an acid having a pKa of not more than 4,    -   (d) a liquid medium containing an alcohol of 1-6 carbon atoms        and water and having a water content, as represented by the        following Expression 1, of 10-500,000 ppm,    -   (e) a polymerization pressure P of not lower than 5 MPa and a        polymerization temperature T of 50-200° C.,        $\text{Water~~~content~~~(ppm)} = {\frac{\text{Mass~~~of~~~water~~~}(g)}{\begin{matrix}        \text{Volume~~~of~~~polymerization~~~solvent~~~other} \\        {\text{than~~~water~~~(ml)} + \text{Volume~~~of~~~water~~~(ml)}}        \end{matrix}} \times 10^{6}}$        1 the volume in the denominator of the right side is a value at        25° C.).

(xvi) A method for producing a polyketone of (xv), wherein thepolymerization temperature is 70-200° C. and the polymerization pressureis not lower than 7 MPa.

(xvii) A method for producing a polyketone of (xv) or (xvi), wherein (a)is at least one palladium compound selected from the group consisting ofpalladium acetate, palladium trifluoroacetate, palladium acetylacetonateand palladium chloride;

-   -   (b) is at least one phosphorus bidentate ligand selected from        the group consisting of        1,3-bis{di(2-methoxyphenyl)phosphino}propane,        1,3-bis(diphenylphosphino)propane,        1,2-bis[{di(2-methoxyphenyl)phosphino}methyl]benzene, and        1,3-bis{di(2-methoxy-4-sodium        sulfonate-phenyl)phosphino}propane;    -   (c) is at least one acid selected from the group consisting of        sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic        acid and trifluoroacetic acid; and    -   (d) is a solvent containing at least one alcohol selected from        the group consisting of methanol, ethanol, n-propanol and        isopropanol.

(xviii) A method for producing a polyketone of any one of (xv)-(xvii),wherein the copolymerization is carried out in the presence ofbenzoquinone or naphthoquinone.

(xix) A method for producing a polyketone of any one of (xv)-(xiix),wherein the molar ratio of ethylenically unsaturated compound/carbonmonoxide in the reaction vessel is 1/1-5/1.

(xx) A method for producing a polyketone of any one of (xv)-(xix),wherein the amount of the palladium compound used is 0.01-10,000micromoles per 1 liter of the polymerization solvent, and the amount ofthe bidentate ligand having an atom of Group 15 elements and the amountof the acid having a pKa of not more than 4 based on 1 mole of thepalladium compound are 0.1-10 moles and 0.1-10000 moles, respectively.

(xxi) A method for producing a polyketone of any one of (xv)-(xx),wherein the content of the alcohol of 1-6 carbon atoms in the liquidmedium (d) is not less than 75 vol %.

(xxii) A method for producing a polyketone of any one of (xv)-(xxi),wherein the acid having a pKa of not more than 4 is sulfuric acid andthe polymerization solvent contains an alcohol of 1-6 carbon atoms andwater, the water content being 10-500000 ppm.

(xxiii) A method for producing a polyketone of any one of (xv)-(xxii),wherein the polymerization pressure P (MPa) and the polymerizationtemperature T (0° C.) satisfy both of the following expressions 2 and 3:P≧720×exp(−0.0629×T)   Expression 2:P≧0.0179×exp(0.0607×T)   Expression 3:

(xxiv) A method for producing a polyketone having an intrinsic viscosityof 3.0-20 dl/g by copolymerizing carbon monoxide and an ethylenicallyunsaturated compound, wherein the polymerization activity is 10kg/g-Pd-hr or higher.

(xxv) A method for producing a polyketone having an intrinsic viscosityof 2.5-20 dl/g by copolymerizing carbon monoxide and an ethylenicallyunsaturated compound, wherein the polymerization activity is not lowerthan 20 kg/g-Pd-hr and the catalyst efficiency (kg/g-Pd) expressed bythe product of the polymerization activity and the polymerization time(hr) is not less than 50.

BEST MODE FOR CARRYING OUT THE INVENTION

In the polyketone of the present invention, 95-100 mol % of therepeating units are 1-oxotrimethylene represented by the formula (1). Ifthe proportion of 1-oxotrimethylene is less than 95 mol %, thecrystallinity of the polyketone greatly lowers, and it becomes difficultto obtain a polyketone molded product with high strength and highmelting point. With the increase of the proportion of 1-oxotrimethylene,the resulting polyketone molded product is superior in the strength,elastic modulus and melting point, and therefore the proportion ispreferably 97 mol % or more, most preferably 100 mol %.

The repeating units other than 1-oxotrimethylene are not particularlylimited, and are generally those which are formed by bonding of carbonmonoxide and ethylenically unsaturated compounds other than ethylene.Examples of the ethylenically unsaturated compounds include α-olefinssuch as propylene, 1-butene, 1-hexene, 1-octene and 1-decene; alkenylaromatic compounds such as styrene and α-methylstyrene; cyclic olefinssuch as cyclopentene and norbornene; halogenated vinyl compounds such asvinyl chloride; acrylic acid ester compounds such as ethyl acrylate andmethyl methacrylate; and the like. These repeating units derived fromcarbon monoxide and ethylenically unsaturated compounds may comprise oneunit or a mixture of two or more units.

If the intrinsic viscosity of the polyketone of the present invention istoo low, molded products with high mechanical characteristics, such ashigh strength and high elastic modulus cannot be obtained, and hence itmust be 2.5 dl/g or higher. On the other hand, if the intrinsicviscosity is too high, moldability, solubility in solvents andproductivity are deteriorated, and hence it must be 20 dl/g or lower.From the viewpoints of the physical properties and the ability to passthe production process of the resulting molded products, the intrinsicviscosity is more preferably 3.0-15 dl/g, further preferably 3.5-10dl/g, most preferably 4-8 dl/g.

It is necessary that the content of Pd element in the polyketone of thepresent invention is 20 ppm or less. If the content of Pd elementexceeds 20 ppm, thermal modification and chemical reactions caused bythe remaining Pd readily take place, resulting in phenomena such as anincrease of melt viscosity during melt molding and an increase ofviscosity of dopes when the polyketone is dissolved in a solvent, tocause the deterioration of the processability. Furthermore, Pd elementalso remains in a large amount in the molded product of polyketone,which causes the deterioration of the heat resistance of the moldedproduct. From the viewpoints of the ability to pass through theproduction process and the heat resistance of the molded product, thecontent of Pd element in the polyketone is preferably as small aspossible, and more preferably 10 ppm or less, further preferably 5 ppmor less, most preferably 0 ppm.

The polyketone of the present invention have two kinds of terminalgroups, namely, an alkyl ester group (terminal group A) represented bythe formula (2) and an alkyl ketone group (terminal group B) representedby the formula (3).

In the present invention, it is necessary that the carbon number of R¹which constitutes the terminal group A is 1-6. When the carbon number ofR¹ is 7 or more (namely, when an alcohol having 7 or more carbon atomsis used as a polymerization solvent), there occur the followingproblems:

-   -   (1) polymerization of polyketone with high polymerization        activity becomes difficult, and a lengthy reaction is required        for producing a polyketone with low Pd content, resulting in the        deterioration of productivity;    -   (2) viscosity of polymerization suspension increases, and        uniform stirring becomes difficult;    -   (3) boiling point of the solvent rises and the recovery cost        increases; and the like. From the viewpoints of the        polymerization activity and productivity, the carbon number of        R¹ is more preferably 1-4. As a preferred structure of the        terminal group A, mention may be made of methyl ester group        having 1 carbon atom (formula (4)) and isopropyl ester group        having 4 carbon atoms (formula (6)).

When the carbon number is within the range of 1-6, the structure of R¹may be of straight chain, may have branches or may be cyclic, andfurthermore may include two or more groups differing in the chain lengthor shape.

In the present invention, it is necessary that R² which constitutes theterminal group B is an organic group of 1-10 carbon atoms. Examples ofthe organic groups of 1-10 carbon atoms are hydrocarbon groups such asmethyl group, ethyl group, n-propyl group, isopropyl group, n-butylgroup, n-pentyl group, n-heptyl group, phenyl group and benzyl group. Apart or the whole of these hydrocarbon groups or a part or the whole ofhydrogen atoms may be optionally substituted with an ester group, anether group, a carbonyl group, an amino group, an amide group, a halogenatom, or the like. When the carbon number of the organic groups exceeds10, the crystallinity of the resulting polyketone lowers and the heatresistance deteriorates. Therefore, the carbon number of R² is morepreferably 2-6, further preferably 2-3, especially preferably 2. Apreferred structure of the terminal group B is specifically an ethylketone group having 2 carbon atoms (the formula (5)).

The polyketone of the present invention may have terminals other thanthe terminal group A and the terminal group B, such as a carboxylic acidterminal group, an alcohol terminal group and an alkyl ester terminalgroup of 7 or more carbon atoms, with a proviso that these terminalgroups are present at an equivalent ratio of 20% or less in all theterminal groups.

In the case where carboxylic acid terminal groups are contained in apolyketone, if the amount of the carboxylic acid terminal group islarge, the heat resistance of the polyketone deteriorates and the heatdeterioration is apt to occur during molding or use. Therefore, theamount of the carboxylic acid terminal groups in the polyketone ispreferably 10 milli-equivalent/kg or less, more preferably 5milli-equivalent/kg or less, most preferably 0 milli-equivalent/kg.

In the present invention, it is necessary that the equivalent ratio ofterminal group A/terminal group B is 0.1-8.0. When the ratio of terminalgroup A/terminal group B is 0.1-8.0, the polyketone is excellent in theheat stability in a metal salt solvent, such as aqueous zinc chloridesolution, and molded products with stable quality can be obtained.

If the equivalent ratio of terminal group A/terminal group B is lessthan 0.1, the quality of the polymer is deteriorated during thepolymerization or treatments after the polymerization.

On the other hand, the ratio of terminal group A/terminal group Bexceeds 8.0, problems such as modification of polymer and deteriorationof processability caused by three-dimensional crosslinking due to alengthy heat treatment or dissolution in solvents occurs conspicuously.From the viewpoints of heat resistance, chemical resistance,productivity and cost, the ratio of terminal group A/terminal group B ispreferably 0.2-4.0, more preferably 0.3-3.0, further preferably 0.5-2.5,especially preferably 1.0-2.0.

In this case, the ratio of terminal groups in the polyketone can beobtained from the ratio of area of the peak resulting from the alkylester terminal group and area of the peak resulting from the alkylketone terminal group which are measured by the known method (¹H-NMRmethod).

The melting point of the polyketone of the present invention ispreferably 220° C. or higher, more preferably 240° C. or higher, furtherpreferably 250° C. or higher from the viewpoint of the heat resistanceof the resulting molded product.

The polyketone of the present invention is less in Pd content and isexcellent in thermal moldability and heat resistance. The heatresistance can be evaluated by DSC melting point Tm³ measured by themethod described in the Examples of the present invention. When anoperation of heating the polyketone from a room temperature to atemperature higher than the melting point and again cooling to the roomtemperature is repeated, thermal modification such as formation of furanring or aldol condensation proceeds during the heating to a temperaturehigher than the melting point. When the polyketone is cooled to atemperature lower than the melting point the thermally modified portionbecomes irregular in structure and cannot be crystallized andaccordingly crystallinity of the polyketone is deteriorated. The lessthe thermal modification, the less the deterioration in crystallinity ofthe polyketone. As a result, the melting point in the case of re-heatingis also kept high. The DSC melting point Tm³ is the melting point of thepolyketone after repeating the heating and cooling treatments, and thehigher DSC melting point means that the crystallinity of polyketone issatisfactory and the thermal modification hardly occurs. Specific valueof the DSC melting point Tm³ is preferably 230° C. or higher. The DSCmelting point Tm³ is more preferably 235° C. or higher, furtherpreferably 240° C. or higher.

The polyketone of the present invention undergoes less thermalmodification such as chemical crosslinking because it is not exposed toexcess heat history such as long-term polymerization or solventextraction treatment. This polyketone which undergoes less thermalmodification has the advantages of excellent processability such as heatmoldability or solution moldability, as well as excellent heatresistance characteristics of molded products. As a specific method formeasuring the degree of thermal modification of polyketone, there is amethod of ultraviolet spectrum measurement of hexafluoroisopropanolsolution as described in the Examples given hereinafter. It is preferredthat the minimum value of absorbance in the ultraviolet absorptionspectrum is 0.14 or less. This minimum value of absorbance correspondsto the degree of crosslinked structure formed by the thermalmodification of polyketone, and the smaller the minimum value, thesmaller the deterioration of polyketone caused during polymerization,and washing and drying of the polymer. The polyketone having the smallerminimum value has superior processability, and the resulting moldedproduct has superior thermal characteristics. Therefore, the minimumvalue of absorbance is more preferably 0.13 or less, especiallypreferably 0.12 or less.

Furthermore, in addition to Pd, phosphorus compounds or acids used aspolymerization catalysts also remain as impurities in the polyketone. Incase these compounds remain in large amounts, there occur not only theproblems of the deterioration and discoloration during storage ofpolyketone, but also the problems of modification of polyketone duringmolding, deterioration of heat resistance and discoloration of moldedproducts. Therefore, the amount of phosphorus element in polyketone ispreferably 20 ppm or less, more preferably 10 ppm or less, furtherpreferably 5 ppm or less, especially preferably 0 ppm. Moreover, whenacids containing sulfur element, such as sulfuric acid, methanesulfonicacid and trifluoromethanesulfonic acid are used for polymerization, theamount of sulfur element remaining in polyketone is preferably 20 ppm orless, more preferably 10 ppm or less, further preferably 5 ppm or less,especially preferably 0 ppm.

The from of polyketone of the present invention after polymerization isnot particularly limited, and the polyketone may be in any forms. In thecase of producing the polyketone by suspension polymerization, theresulting polyketone is in the form of particles or flakes, and from theviewpoint of solubility in solvent, it is preferably in the form ofparticles. The size or shape of the particles is not particularlylimited, but from the viewpoints of handleability and solubility insolvents, the average particle diameter is preferably 0.01-2 mm, morepreferably 0.1-1 mm. The shape of the particles is especially preferablyspherical.

Furthermore, from the viewpoints of storage stability andtransportability, the higher bulk density of the resulting polyketone ispreferred, and from the viewpoint of solubility in solvents, the lowerbulk density is preferred. From the viewpoint of the balance between thetransportability and the solubility, the bulk density is preferably 5-50g/100 ml, more preferably 20-45 g/100 ml, especially preferably 30-40g/100 ml.

If necessary, the polyketone of the present invention may containvarious additives, such as heat stabilizer, anti-foaming agent,orthochromatic agent, flame retardant, anti-oxidant, ultravioletabsorber, infrared absorber, crystal nucleating agent, and surfaceactive agent.

Regarding the molded products made from the polyketone of the presentinvention, it is necessary from the viewpoints of mechanical strength,thermal characteristics and heat resistance that 95-100 mole % of therepeating units are 1-oxotrimethylene, the intrinsic viscosity is 2.5-20dl/g, the equivalent ratio of terminal group A/terminal group B is0.1-8.0, and the content of Pd element is not more than 20 ppm.

If the proportion of 1-oxotrimethylene of the polyketone thatconstitutes the polyketone molded product is less than 95 mole %, thecrystallinity is considerably deteriorated, and it is difficult toobtain a polyketone molded product with high strength and high meltingpoint. The higher proportion of 1-oxotrimethylene gives excellentstrength, elastic modulus and melting point to the resulting polyketonemolded product, and the proportion is preferably 97 mol % or more,especially preferably 100 mol %.

The repeating units other than 1-oxotrimethylene are not particularlylimited, and generally they are units comprising carbon monoxide and anethylenically unsaturated compound other than ethylene which are bondedto each other. Examples of the ethylenically unsaturated compoundsinclude α-olefins such as propylene, 1-butene, 1-hexene, 1-octene and1-decene; alkenyl aromatic compounds such as styrene anda-methylstyrene; cyclic olefins such as cyclopentene, norbornene,5-methylnorbornene, tetracyclodecene, tricyclodecene,pentacyclopentadecene and pentacyclohexadecene; halogenated vinyls suchas vinyl chloride; acrylic acid esters such as ethyl acrylate and methylmethacrylate; and the like. These repeating units derived from carbonmonoxide and ethylenically unsaturated compounds may comprise singleunit or a mixture of two or more units.

The intrinsic viscosity of the polyketone molded products is required tobe not lower than 2.5 dl/g for obtaining the high mechanical physicalproperties. If the intrinsic viscosity is too high, the processabilityand productivity deteriorate to increase the cost, and hence it isneeded to be not higher than 20 dl/g. From the viewpoints of thephysical properties and the ability to pass the production process andthe productivity of the molded products, the intrinsic viscosity is morepreferably 3.0-15 dl/g, further preferably 3.5-10 dl/g, especiallypreferably 4-8 dl/g.

It is necessary that the polyketone molded product of the presentinvention has a content of Pd element of not more than 20 ppm. If thecontent of Pd element exceeds 20 ppm, the ability to pass the productionprocess is inferior and the heat resistance of the molded product alsolowers. Therefore, the content of Pd element in the polyketone moldedproduct is preferably as low as possible, and is more preferably 10 ppmor lower, further preferably 5 ppm or lower, especially preferably 0ppm.

Moreover, when the polyketone molded product is molded by dissolving thepolyketone in a concentrated aqueous solution of a metal salt, such aszinc chloride, followed by carrying out molding, the metal in thesolvent sometimes remains in the molded product. The remaining metaladversely affects the heat resistance or mechanical properties of thepolyketone molded product, and the amount of the remaining metal ispreferably as small as possible. Specifically, the amounts of, forexample, Zn element and Ca element are preferably 50 ppm or less, morepreferably 20 ppm or less, and especially preferably 0 ppm.

In the present invention, it is necessary that the equivalent ratio ofterminal group A/terminal group B in the polyketone molded product is0.1-8.0. If the ratio of terminal group A/terminal group B is less than0.1, problems are apt to occur in the processability and long-term heatstability. If the ratio of terminal group A/terminal group B exceeds8.0, there are apt to occur problems such as modification of polymer anddeterioration of processability during heat treatment or dissolution ina metal salt solvent. From the viewpoints of the heat resistance,chemical resistance, productivity and cost, the ratio of terminal groupA/terminal group B is preferably 0.2-3.0, more preferably 0.5-2.5,further preferably l.0-2.0.

Furthermore, there may be present terminals other than the terminalgroup A and the terminal group B, such as carboxylic acid terminal groupand alcohol terminal group, with a proviso that they are present in anamount of not more than 20 mol % of the total terminal groups. In thecase of containing the carboxylic acid terminal group, the heatresistance of the polyketone molded product lowers if the amount of thecarboxylic acid terminal group is large. Therefore, the amount of thecarboxylic acid terminal group in the polyketone molded product ispreferably 10 milli-equivalent/kg or less, more preferably 5milli-equivalent/kg or less, especially preferably 0milli-equivalent/kg.

As for the specific mechanical characteristics, in the case of using asfibers, the strength of the fibers is preferably 10 cN/dtex or higher,more preferably 12 cN/dtex or higher, especially preferably 15 cN/dtexor higher, and the initial elastic modulus is preferably 200 cN/dtex orhigher, more preferably 300 cN/dtex or higher, especially preferably 350cN/dtex or higher. As for the specific thermal characteristics, themelting point is preferably 240° C. or higher, more preferably 250° C.or higher, especially preferably 260° C. or higher. In the case wherethe catalyst residues such as Pd and P are present in large amounts, thefibers are gradually deteriorated during the long-term use,nevertheless, it becomes possible by using the polyketone molded productof the present invention to maintain the excellent thermalcharacteristics and mechanical characteristics for a long time withoutdamaging durability.

Next, the method for producing the polyketone of the present inventionwill be explained below.

The polyketone of the present invention can be produced bycopolymerizing carbon monoxide and an ethylenically unsaturated compoundunder the following conditions (e) in the following liquid medium (d) inthe presence of a metal complex catalyst obtained by reacting thefollowing compounds (a)-(c):

-   -   (a) a palladium compound,    -   (b) a bidentate ligand having an atom of Group 15 elements,    -   (c) an acid having a pKa of not more than 4,    -   (d) a liquid medium containing an alcohol of 1-6 carbon atoms        and water and having a water content, as represented by the        following Expression 1, of 10-500,000 ppm.        Expression 1:        $\text{Water~~~content~~~(ppm)} = {\frac{\text{Mass~~~of~~~water~~~}(g)}{\begin{matrix}        \text{Volume~~~of~~~polymerization~~~solvent~~~other} \\        {\text{than~~~water~~~(ml)} + \text{Volume~~~of~~~water~~~(ml)}}        \end{matrix}} \times 10^{6}}$    -   (e) a polymerization pressure P of not lower than 5 MPa and a        polymerization temperature T of 50-200° C.

The catalyst used for the polymerization in the present invention is ametal complex obtained by blending a palladium compound, a bidentateligand having an atom of Group 15 elements and an acid having a pKa ofnot more than 4.

Examples of the palladium compound (a) include carboxylates, phosphates,carbamates, sulfonates and halides of palladium, and specific examplesinclude palladium acetate, palladium trifluoroacetate, palladiumacetylacetonate, palladium chloride, bis(N,N-diethyl carbamate),bis(diethylamino)palladium, and palladium sulfate. These may be usedeach alone or in admixture of several kinds. From the viewpoints of thepolymerization activity, stability of the metal complex and recoverycost, preferred compounds are palladium acetate, palladiumtrifluoroacetate, palladium acetylacetonate and palladium chloride, andpalladium acetate is especially preferred.

The ligand used for the metal complexes is bidentate ligand (b) havingan atom of Group 15, and as examples thereof, mention may be made ofnitrogen bidentate ligands, such as 2,2′-dipyridyl,4,4′-dimethyl-2,.2′-dipyridyl, 2,2′-di-4-picoline and 2,2′-diquinoline;phosphorus bidentate ligands, such as 1,2-bis(diphenylphosphino)ethane,1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane,1,3-bis{di(2-methyl)phosphino}propane,1,3-bis{di(2-isopropyl)phosphino}propane,1,3-bis{di(2-methoxyphenyl)phosphino}propane,1,3-bis{di(2-methoxy-4-sodium sulfonate-phenyl)phosphino}propane,1,2-bis(diphenylphosphino)cyclohexane,1,2-bis(diphenylphosphino)benzene,1,2-bis{(diphenylphosphino)methyl}benzene,1,2-bis[{di(2-methoxyphenyl)phosphino}methyl]benzene,1,2-bis[{di(2-methoxy-4-sodiumsulfonate-phenyl)phosphino}methyl]benzene,1,1′-bis(diphenylphosphino)ferrocene,2-hydroxy-1,3-bis{di(2-methoxyphenyl)phosphino}propane, and2,2-dimethyl-1,3-bis{di(2-methoxyphenyl)phosphino}propane, and the like.

Among them, more preferred are phosphorus bidentate ligands. From theviewpoints of obtaining polyketones with high polymerization activityand high molecular weight, preferred phosphorus bidentate ligands are1,3-bis{di(2-methoxyphenyl)phosphino}propane,1,3-bis(diphenylphosphino)propane,1,2-bis[{di(2-methoxyphenyl)phosphino}methyl]benzene, and1,3-bis{di(2-methoxy-4-sodium sulfonate-phenyl)phosphino}propane, andfrom the viewpoint of producing polyketones with high molecular weightin industrial scale, 1,3-bis(diphenylphosphino)propane and1,3-bis{di(2-methoxyphenyl)phosphino}propane are especially preferred.

The acids (c) having a pKa of 4 or less include, for example, organicacids, such as trifluoroacetic acid, methanesulfonic acid,trifluoromethanesulfonic acid, and p-toluenesulfonic acid; inorganicacids, such as perchloric acid, sulfuric acid, nitric acid, phosphoricacid, heteropoly acid, tetrafluoroboric acid, hexafluorophopshoric acidand fluorosilicic acid; boron compounds, such astrispentafluorophenylborane,trisphenylcarbeniumtetrakis(pentafluorophenyl) borate andN,N-dimethylaniliumtetrakis(pentafluorophenyl) borate; and the like.These acids can be used each alone or in admixture of two or more.

From the viewpoint that polyketones with high molecular weight can beobtained with high polymerization activity, preferable acids aresulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid andtrifluoroacetic acid. The pKa is a value defined as pKa=−log₁₀Ka when adissociation constant of the acid is indicated by Ka, and the smallerthe pKa value, the stronger the acids.

Regarding the amount of the palladium compound (a), the suitable amountvaries depending on the kind of the ethylenically unsaturated compoundselected and other polymerization conditions, and hence the range cannotunconditionally be determined. However, the amount is preferably0.01-10,000 micromoles, more preferably 0.1-1,000 micromoles per 1 literof the liquid medium used for polymerization.

The amount of the bidentate ligand (b) is not limited, and is preferably0.1-10 moles, more preferably 1-3 moles, especially preferably 1.1-1.3mole per 1 mole of the palladium compound.

The amount of the acid having a pKa of not more than 4 is preferably0.1-10000 moles, more preferably 1-1000 moles, especially preferably2-100 moles per 1 mol of palladium.

The metal complex used for the catalyst in the present invention isproduced by contacting the palladium compound, the bidentate ligandhaving an atom of Group 15 elements and the acid having a pKa of notmore than 4. Any method can be employed for contacting them. Forexample, the three components may be used as a solution prepared bypreviously mixing them in a suitable solvent or the three components maybe separately supplied to the polymerization system and contacted in thepolymerization system. Alternatively, a complex obtained by previouslyreacting the palladium compound with the bidentate ligand having an atomof Group 15 elements may be allowed to contact with the acid having apKa of not more than 4.

The form of the metal complex and procedure of preparation of the metalcomplex are not particularly limited, but preferably a metal complexcomprising a mixture of (a)-(c) is previously prepared and is added intoa reaction vessel. In this case, it is preferred that first thepalladium compound (a) and the bidentate ligand (b) are mixed, and thenthe acid (c) is mixed therewith. Solvents used for the preparation ofthe metal complex may be alcohols, such as methanol, or non-protonicorganic solvents, such as acetone and methyl ethyl ketone.

The polymerization of polyketone is carried out by contacting carbonmonoxide and the ethylenically unsaturated compound with the metalcomplex through a liquid medium. From the viewpoint of producingpolyketone with a high polymerization activity, the liquid medium(hereinafter sometimes referred to as “polymerization solvent”) isrequired to be a liquid medium containing an alcohol of 1-6 carbon atomsand water and having a water content represented by the Expression 1 of10-500,000 ppm. In Expression 1, the volumes of the liquid media in thedenominator of the right side are values at 25° C.

When the polymerization is carried out in a polymerization solventcontaining no hydroxyl group, such as acetone, tetrahydrofuran anddimethyl sulfoxide, the polymerization rate is very low and thepolyketone of the present invention which is small in Pd content cannotbe obtained. Furthermore, when the polymerization is carried out in apolymerization solvent containing only the alcohol of 7 or more carbonatoms, the polymerization rate is also very low and the polyketone witha small Pd content cannot be obtained, either. In the case of usingthese polymerization solvents, the equivalent ratio of terminal groupA/terminal group B of the resultant polyketone is less than 0.1, andunder these conditions, it is difficult to produce polyketone with ahigh polymerization activity, and the quality of the resultingpolyketone is deteriorated.

The carbon number of the alcohol contained in the polymerization solventmust be 6 or less, and is preferably 4 or less from the viewpoint ofobtaining a higher polymerization activity. Specific compounds includemethanol, ethanol, butanol, n-propanol, isopropanol, etc. From theviewpoints of the handleability, polymerization activity and increase inmolecular weight, methanol and isopropanol are particularly preferred.These alcohols may be used each alone or in admixture.

The content of the alcohol of 1-6 carbon atoms in the polymerizationsolvent is not particularly limited, but is preferably 20 vol % or morefrom the viewpoint of producing the polyketone with high polymerizationactivity. With the increase of the content of the alcohol, thepolymerization activity becomes higher, and hence the amount of thealcohol of 1-6 carbon atoms in the polymerization solvent is preferably50 vol % or more, more preferably 75 vol % or more.

Furthermore, in order to obtain the polyketone of the present inventionwhich is low in the Pd content, it is necessary that the water contentrepresented by the Expression 1 in the polymerization solvent is10-500,000 ppm. In the present invention, when the catalyst is dissolvedin a liquid medium and the resulting catalyst solution is added to thepolymerization solvent, the catalyst solution is also regarded to be apart of the polymerization solvent, and the volume of the catalystsolution is added to the denominator of the right side of Expression 1,and when water is used for the catalyst solution, this is added to thenumerator of the right side of the Expression 1, and thus the watercontent is obtained.

If the water content in the polymerization solvent is less than 10 ppm,the polymerization activity cannot be sufficiently enhanced even when analcohol of 1-6 carbon atoms is used for the polymerization solvent. Onthe other hand, when the water content in the polymerization solvent is10 ppm or more, the effect of enhancing the polymerization activity isexhibited. If the water content is more than 500,000 ppm, however, themolecular weight does not increase, though the polymerization activityincreases. As a result, it becomes difficult to produce a polyketonehaving an intrinsic viscosity of not lower than 2.5 dl/g. The preferredwater content is 500-200,000 ppm. Moreover, when water is present in anamount of 100-10,000,000 fold moles with respect to the palladiumcompound and in an amount of 1-50,000 fold moles with respect to theacid having a pKa of not more than 4, the polymerization activity isfurther improved, which is preferred.

Furthermore, in the polymerization solvent, an organic solvent, e.g., aketone such as acetone or methyl ethyl ketone, an ether such as diethylether or tetrahydrofuran, or the like may be used together.

A metal complex is added to the above polymerization solvent as acatalyst to carry out the polymerization of polyketone in a reactionvessel, such as an autoclave, in the presence of an ethylenicallyunsaturated compound and carbon monoxide under the conditions of apolymerization pressure P of 5 MPa or higher and a polymerizationtemperature T of 50-200° C. If the polymerization pressure P is lowerthan 5 MPa, it is difficult to carry out the polymerization with highpolymerization activity, and the polyketone of the present invention lowin Pd content cannot be produced. Therefore, the polymerization pressureP is required to be 5 MPa or higher. As the polymerization pressurebecomes higher, the polymerization activity also becomes higher tolessen the Pd content in the polyketone and improve the productivity.Therefore, the polymerization pressure is preferably 7 MPa or higher,more preferably 10 MPa or higher, further preferably 15 MPa or higher.

On the other hand, when the polymerization pressure is too high,equipments, such as reaction vessel and piping, are become heavy, whichleads to the increase of costs for producing the equipments. Therefore,the pressure at the time of polymerization is desirably 300 MPa orlower, more preferably 100 MPa or lower and further preferably 30 MPa orlower.

It is necessary that the polymerization temperature T is 50° C. orhigher. If the polymerization temperature is lower than 50° C., thepolyketone can hardly be produced with high polymerization activity evenif the polymerization pressure is raised. As the polymerizationtemperature becomes higher, the polymerization activity also becomeshigher to lessen the Pd content in the polyketone decreases andproductivity is improved. Therefore, the polymerization temperature ispreferably 70° C. or higher, more preferably 80° C. or higher.

On the other hand, when the polymerization temperature is too high, thepolymerization termination reaction rate becomes too high, and itbecomes difficult to produce a polyketone with high molecular weightwhich has an intrinsic viscosity of not lower than 2.5 dl/g. Therefore,the polymerization temperature is required to be 200° C. or lower,preferably 120° C. or lower, more preferably 100° C. or lower.

From the viewpoint of obtaining a polyketone with high molecular weightwith high polymerization activity, the polymerization pressure P and thepolymerization temperature T are preferably within the ranges ofExpressions 2 and 3.

Expression 2 shows a preferable pressure range for obtaining apolymerization activity of 10 kg/g-Pd·hr or higher at temperature T, andExpression 3 shows a preferable pressure range for obtaining anintrinsic viscosity of 2.5 dl/g or higher at temperature T.

From the viewpoints of carrying out the polymerization for a long timewith maintaining high polymerization activity, it is preferred to add,as additives, quinones such as benzoquinone, naphthoquinone andanthraquinone, metal salt compounds such as copper chloride, aluminumchloride and iron chloride, and the like. Benzoquinone andnaphthoquinone have high effect of maintaining the polymerizationactivity and hence are preferred. The amount of the additives ispreferably 10-10,000 moles, more preferably 50-500 moles per 1 mole ofthe palladium compound (a). The quinones may be added by any of themethod of adding them to a catalyst composition and charging them in thereaction vessel and the method of adding them to the polymerizationsolvent, and if necessary, they may be continuously charged in thereaction vessel during the reaction.

The above-mentioned catalyst composition and optional additives areadded to the above polymerization solvent and the polymerization iscarried out in a reaction vessel such as autoclave in the presence ofthe ethylenically unsaturated compound and carbon monoxide under thefollowing conditions.

The proportion of carbon monoxide and the ethylenically unsaturatedcompound is preferably 2/1-1/15, more preferably 1/1-1/10 in molar ratioof carbon monoxide/ethylenically unsaturated compound, from theviewpoints of polymerization activity and recovery cost, and ispreferably 1/2-1/5, from the viewpoint that the polymerization activitycan be increased. The method for addition of carbon monoxide andethylenically unsaturated compound is not particularly limited, and theymay be previously mixed and then added, or they may be added fromseparate feeding lines, respectively.

In the case of producing the polyketone by a suspension polymerizationmethod, the volume ratio of gas phase/liquid phase is preferably1/50-1/1 from the viewpoint of producing the polyketone in a largeramount per capacity of the reaction vessel, and is preferably 1/10-5/1from the viewpoints of dissolution rate of carbon monoxide and ethylenein the liquid phase and control of the reaction. From the viewpoints ofpolymerization activity, productivity, controllability of reaction andcost, the volume ratio of gas phase/liquid phase is more preferably1/30-1/1.

The polymerization time for the polyketone is preferably 1-24 hours. Ifthe polymerization time is less than 1 hour, the Pd content in thepolyketone is high, and a particular step for removing the catalyst isrequired, resulting in the deterioration of productivity. On the otherhand, if the polymerization time exceeds 24 hours, yield of polyketoneper a given time deceases and productivity is deteriorated. Thepolymerization time is more preferably 1.5-10 hours, especiallypreferably 2-6 hours.

The polymerization time in the present invention means the time from thepoint of time when carbon monoxide and the ethylenically unsaturatedcompound are introduced into a reaction vessel which contains the abovecatalyst composition and polymerization solvent and is under theabove-mentioned polymerization conditions till the point of time whenthe atmosphere in the reaction vessel is converted to a state wheresubstantially no reaction takes place, for example, by lowering thetemperature or releasing the internal pressure. In the case of thecontinuous polymerization method according to which carbon monoxide andethylenically unsaturated compound are continuously introduced into thereaction vessel and the polymerization products are continuouslydischarged, an average residence time from the introduction to thedischarging is taken as the polymerization time.

As to the method for producing polyketone according to the presentinvention, it is preferred that the polymerization activity is high,from the viewpoint of obtaining a polyketone with a content of Pdelement of 20 ppm or less at an industrial cost. The polymerizationactivity in the present invention is a numerical value calculated inaccordance with the following Expression 4, and the greater value meansthat the amount of polyketone obtained per unit of Pd amount and unit ofpolymerization time is greater, in other words, that the amount of Pdrequired for obtaining the same amount of polyketone is smaller and thetime required for polymerization is shorter.Expression 4:$\left. {\text{Polymerization~~~activity~~~~(kg/g} - {{Pd}\text{/}{hr}}} \right) = \frac{\text{Yield~~~of~~~polyketone~~~(Kg)}}{\begin{matrix}{\text{Amount~~~of~~~}{Pd}\quad\text{used~~~for~~~catalyst}\quad(g) \times} \\\text{polymerization~~~time~~~(hr)}\end{matrix}}$

Even when the polymerization activity is low, the amount of Pd elementin the polyketone can be reduced by prolonging the polymerization time,but when the polymerization time is prolonged, there occur such problemsthat a large amount of an oxidizing agent is required for inhibitingdeactivation of the catalyst and productivity lowers.

The polymerization activity is preferably 10 kg/g-Pd·hr or higher. Fromthe viewpoints of productivity and cost of Pd used for the resultingstarting materials, the polymerization activity is more preferably 20kg/g-Pd·hr or higher, further preferably 30 kg/g-Pd·hr or higher,especially preferably 40 kg/g-Pd·hr or higher.

In order to reduce the amount of Pd element in the polyketone to notmore than 20 ppm without employing the steps such as washing and removalof catalyst, it is preferred to produce a polyketone containing not morethan 20 ppm of Pd element only by the polymerization step, and in thiscase, the catalyst efficiency (kg/g-Pd) expressed by the product of thepolymerization activity (kg/g-Pd·hr) and the polymerization time (hr) ispreferably 50 (kg/g-Pd) or higher. The higher the catalyst efficiency,the smaller the amount of Pd element in the polyketone. Hence thecatalyst efficiency is more preferably 100 or higher, further preferably200 or higher.

The polymerization method of polyketone is not particularly limited, andknown polymerization methods and production processes can be used. Forexample, the polymerization methods include a suspension polymerizationmethod using a liquid medium, a gas phase polymerization method in whicha small amount of polymer is impregnated with a high concentrationcatalyst solution, and the like. The process may be either of a batchtype process or a continuation type process.

A preferred embodiment of polymerization process will be described inreference to an example of the suspension polymerization method ofpolyketone comprising carbon monoxide and ethylene.

Carbon monoxide and ethylene used for the reaction are passed through anabsorption column of at least one stage to remove impurities, such assulfur content, iron content, metal carbonyl, methane and ethane, toperform purification. The purified carbon monoxide and ethylene areseparately or in admixture pressurized to a pressure higher than thereaction pressure by a gas compressor and/or a liquid compressor, and,if necessary, subjected to reduction in pressure, and thereafterintroduced into a reaction vessel at a given molar ratio.

Carbon monoxide and the ethylenically unsaturated compound may beintroduced into either of the gas phase part and the liquid phase partin the reaction vessel. When they are introduced into the gas phasepart, it is preferred to promote the dissolution of them in thepolymerization solvent by stirring the gas-liquid interface. Theproportion of gas-liquid interface area S (cm²)/liquid phase part volumeV (cm³) is preferably 0.1 or higher, more preferably 0.3 or higher. Whenthey are introduced into the liquid phase part, it is preferred topromote the dissolution in the polymerization solvent by stirring theportion around the introduction position.

The reaction vessel may be any of autoclave type and tubular type. Whena reaction vessel of autoclave type is used, a plurality of the reactionvessels may be connected in series, and the polymerization may beeffected in multistage of two or more stages. The inner wall of thereaction vessel is preferably subjected to surface treatments, such asglass lining or Teflon lining.

The catalyst composition is previously prepared in a catalystpreparation apparatus and continuously fed to the reaction vessel at thestarting of the polymerization or during the polymerization.

The catalyst composition, carbon monoxide and ethylene are fed to thepolymerization solvent, and polymerization is carried out under givenconditions of temperature and pressure for a given time.

The bulk density of polyketone is preferably in the range of 5-50 g/100ml, and the bulk density can be adjusted. In order to increase the bulkdensity, an acid such as sulfuric acid, trifluoroacetic acid or aceticacid may be added to the polymerization solvent, or a ketone such asacetone or methyl ethyl ketone may be mixed with the polymerizationsolvent. When an acid is added, it is desirable to add the acid in anamount of 40-5,000 fold moles, preferably 60-1,000 fold moles withrespect to the palladium compound. When a ketone is mixed, desirably itis mixed in an amount of 10-80 vol %, preferably 20-60 vol % of thepolymerization solvent. On the other hand, in order to decrease the bulkdensity, there is, for example, a method of adding an alcohol of 3 ormore carbon atoms, such as isopropanol, t-butanol, 1-hexanol, 1-octanolor the like to the polymerization solvent. When an alcohol of 3 or morecarbon atoms is added, it is desirable to add the alcohol in an amountof 10-80 vol %, preferably 20-60 vol % of the polymerization solvent.

The polyketone after the completion of the polymerization is dischargedfrom the reaction vessel in the state of a suspension. If necessary, thesuspension discharged from the reaction vessel is passed through a flushtank to remove unreacted carbon monoxide and ethylene remaining in thesuspension.

The gas phase component discharged from the reaction vessel and theflush tank is cooled to remove the polymerization solvent to purify itinto unreacted carbon monoxide and ethylene, which are then returned tothe compressor and can be reused for the polymerization.

Then, the polyketone suspension is subjected to two stage step, namely,a step of separating a wet polyketone powder and a liquid component, anda step of drying and removing the liquid component remaining in the wetpolyketone powder, to isolate polyketone.

For separating the polyketone suspension into the wet polyketone powderand the liquid component, it is preferred to use centrifugal classifyingmachines such as liquid cyclone, centrifugal settling machine,centrifugal tilting machine and centrifugal hydro-extractor. From theviewpoints of reducing the amount of the catalyst composition remainingin the polyketone and diminishing the drying energy, it is preferred tocarry out the separation until the amount of the liquid component in thewet polyketone powder reaches preferably 15-50 wt %, more preferably18-30 wt % based on the weight of the polyketone. Furthermore, when theoperation of washing the wet polyketone powder obtained by thecentrifugal separation with the same solvent as used for thepolymerization solvent to dilute the catalyst composition remaining inthe liquid component in the wet powder and then again carrying out thecentrifugal classification are repeated twice or more, the amount of thecatalyst composition remaining in the polyketone can be easily reduced.In the case of using sulfuric acid as an acid, it is preferred to washwith a solvent containing water for efficient removal of the remainingsulfuric acid, and it is more preferred to further wash with a solventcontaining water heated to 30° C. or higher.

The polymerization solvent remaining in the thus-obtained wet polyketonepowder containing 15-50 wt % of the liquid component is dried andremoved by heating to a temperature higher than the boiling point of thepolymerization solvent. As the drying method, there may be used knownapparatuses and methods, such as a method of spraying a heated gas and amethod of passing a heated gas with stirring the polyketone powder. Afluidized bed type dryer is preferred from the viewpoints of dryingspeed and uniformity of drying. The heating temperature is preferably60-150° C., more preferably 70-120° C. from the viewpoints of dryingefficiency and thermal deterioration of polyketone. The heated gas thatis passed through the dryer is preferably nitrogen.

The liquid component removed from the polyketone suspension and theliquid component used for the washing are passed through a distiller toremove low boiling point fractions (oligomers, catalyst composition,quinones, etc.), and, if necessary, they are further passed through afractionator to recover each polymerization solvent component. Therecovered solvents are passed through an absorption column, ifnecessary, and they can be then reused as a solvent for preparation ofcatalyst, a polymerization solvent and a solvent for washing.

When quinones are used for polymerization, the quinones which have actedas an oxidizing agent of Pd is per se reduced to hydroxyquinones. Sincethe hydroxyquinones are catalyst poison, they are preferably removed atthe time of recovery. In the case where a single distillation treatmentis used alone, the hydroxyquinone sublimes and sometimes remains in therecovered solvent. Hence, it is desirable to add an alkali compound suchas sodium hydroxide or calcium hydroxide before distillation to settlethe hydroxyquinones.

The low boiling point fractions are fired and the palladium compound isregenerated and reused as a catalyst. The method for regeneration of thepalladium compound includes, for example, a method of heat treating thelow boiling point fractions at 300-1000° C., preferably 350-700° C. inthe presence of an inert gas, such as nitrogen, followed by carrying outa firing treatment at 300-1000° C., preferably 350-700° C. in anatmosphere containing 10 vol % or more of oxygen, and then treating theresulting firing product with an acidic solution such as acetic acid ornitric acid. The method for regenerating palladium acetate from thefiring product includes, for example, a method of reducing palladium byadding a reducing compound, such as hydrogen, to acetic acid and thenadding concentrated nitric acid to oxidize palladium to obtain palladiumacetate with high purity.

The polyketone obtained by the above production methods and processescan be made to moldings by melt molding or dry molding or wet moldingafter being dissolved in a solvent. For example, in the case of meltmolding, polyketone is molten by heating to a temperature from themelting point to the melting point +50° C. and the melt can be molded bya known molding machine. The molding method can be optionally selecteddepending on the purpose and use, and there may be selected compressionmolding, extrusion molding, blow molding, mold molding, etc.

Furthermore, it is also possible to add 0.1-80 wt % of water topolyketone to plasticize it to carry out the molding at a temperature ofthe melting point of the polyketone −10° C., or lower.

The solvent in the case of molding the polyketone dissolved in a solventis not particularly limited, and there may be used known solvents, forexample, organic solvents, such as hexafluoroisopropanol, m-cresol andresorcinol; and metal salt solutions, such as zinc chloride solution andzinc chloride/calcium chloride solution.

After the polyketone is dissolved in the above solvent to prepare adope, the dope is heated or immersed in a coagulant to extract andremove the solvent from the dope and is molded into desired shapes. Inthe case where an aqueous solution mainly composed of a halogenatedalkali metal salt or halogenated alkaline earth metal, such as zincchloride, lithium chloride or calcium chloride is used as the solvent,there may occur the deterioration of moldability caused by modificationof polyketone or discoloration of the moldings depending on thedissolution conditions or storage conditions. From the viewpoint ofinhibiting the thermal modification of polyketone, the time during whichthe dope is heated to 80° C. or higher is preferably 5 hours or shorter,and, furthermore, if the time from the preparation of the dope until themolding is long, it is desirable to cool the dope to 70° C. or lowerafter the preparation and heat it just before the molding.

The coagulant is preferably a liquid medium in which polyketone isinsoluble, and is preferably an aqueous solution containing 80 wt % ormore of water from the viewpoints of safety and cost. In the case ofusing a metal salt solution containing zinc chloride as a solvent, it isdesirable to further wash the polyketone with an acidic solution, suchas hydrochloric acid, after the coagulation until the amount ofremaining zinc reaches 20 ppm or less, from the viewpoint of the heatresistance of the polyketone molded product.

The polyketone made to an desired shape in the coagulant is successivelyheated or kept in an atmosphere of reduced pressure to extract andremove the coagulant, whereby a polyketone molded product can beobtained. The heating temperature for removing the coagulant by heatingis preferably between the boiling point of the coagulant and the meltingpoint of the polyketone.

Furthermore, if necessary, the polyketone molded product may besuccessively heated and stretched, to process it into a molded producthigh in the crystallinity and excellent in the mechanical properties,such as strength and elastic modulus. The heating and stretchingconditions can be optionally selected depending on the purpose and use.For the application of industrial fibers, the temperature is suitably200-270° C. and the stretching ratio is suitably 5-20 times. Especiallypreferred is a multi-stage stretching in which the stretching inmulti-stages of 2 or more stages are carried out, while the stretchingtemperature is gradually increased.

When the molded product is a polyketone fiber, which is processed tocords and used as a reinforcing material, the number of twist isselected depending on the use. In general, twisting is carried out at atwisting coefficient K in the range of 1000-30000.

In the case where the polyketone is processed to rubber reinforcingfibers, the twisted polyketone cords are as they are or woven in theform of a screen, and then a resorcinol-formalin-latex (RFL) solution isapplied thereto, and the resin is fixed thereon. The composition of theRFL solution comprises desirably 0.1-10 wt % of resorcinol, 0.1-10 wt %of formalin and 1-28 wt % of latex. The drying temperature for RFLsolution is preferably 100-250° C., more preferably 140-200° C., and thedrying by heat treatment is carried out for at least 10 seconds,preferably 20-120 seconds. The cords after drying is successively heattreated. Preferably, the temperature, tension and time for the heattreatment are 150-250° C., 0.01-0.7 cN/dtex, and 10-300 seconds,respectively.

The present invention will be explained specifically by the followingExamples, etc. which should not be construed as limiting the inventionin any manner.

The organic solvents used in the Examples are completely dried solventsobtained by dehydration of solvents for organic synthesis and additionaldehydration with magnesium sulfate under dry nitrogen stream beforepolymerization. Distilled water containing no impurities, such asmetals, was used as water. Sulfuric acid used as the acid was 96 wt %sulfuric acid of special grade chemical. This sulfuric acid contained 4wt % of water, which is taken into consideration when the amounts ofsulfuric acid and water contents in the Examples in the polymerizationare obtained.

The methods for measurement of the values used in the Examples are asfollows.

(1) Intrinsic Viscosity ([η]):

The intrinsic viscosity [η] was obtained in accordance with thefollowing Expression 5.Expression 5:$\lbrack\eta\rbrack = {\lim\limits_{c\rightarrow o}{{{\left( {T - t} \right)/t} \cdot C}\quad\left( {{dl}/g} \right)}}$

In the Expression 5, t and T indicate falling times ofhexafluoroisopropanol having a purity of 98% or higher and a dilutesolution of polyketone in hexafluoroisopropanol through a viscosity tubeat 25° C., and C indicates a mass value in gram unit of the solute in100 ml of the above solution.

(2) Polymerization Activity:

This shows yield of polyketone per unit amount of palladium and unittime, and was calculated in accordance with Expression 7.

(3) Contents of Elements in Polyketone:

The contents of Pd, P, Zn and Ca elements were measured according to aknown method by high-frequency plasma emission spectrochemical analysis.

(4) Ratio of Terminal Groups:

12 milligrams of polyketone was dissolved in a mixed solution of 0.05 mlof heavy hydrogen-containing chloroform and 0.6 ml of deuteratedhexafluoroisopropanol which contained 0.03 wt % of tetramethylsilane,and measurement of ¹H-NMR was conducted using FT-NMR manufactured byBruker Co., Ltd. (trade name: DPX-400). The ratio of terminal groups wasobtained by the following method taking the peak of tetramethylsilane asthe standard peak (0 ppm).

4-1) In the Case of using Methanol as Polymerization Solvent:

Area of a peak observed at around 3.7 ppm (a peak corresponding to˜COOCH₃) is shown by M and area of a peak observed at around 1.1 ppm (apeak corresponding to ˜CH₂CH₃) is shown by K, and M/K is taken as theratio of terminal groups.

4-2) In the Case of using Ethanol as Polymerization Solvent:

Area of a peak observed at around 1.3 ppm (a peak corresponding to˜COOCH₂CH₃) is shown by E and area of a peak observed at around 1.1 ppm(a peak corresponding to ˜CH₂CH₃) is shown by K, and E/K is taken as theratio of terminal groups.

4-3) In the Case of using Isopropanol as Polymerization Solvent:

Area of a peak observed at around 1.2 ppm (a peak corresponding to˜COOCH(CH₃)₂) is shown by P and area of a peak observed at around 1.1ppm (a peak corresponding to ˜CH2CH3) is shown by K, and (P/K)/2 istaken as the ratio of terminal groups.

(5) Dry Heat Resistance Tm³:

5 milligrams of a sample was enclosed in an aluminum pan under anitrogen atmosphere, and measurement was conducted using a differentialthermal measurement device Pyrisl (trade name) manufactured byPerkin-Elmer Co., Ltd. under the following conditions.

-   Weight of sample: 1 mg-   Atmosphere: Nitrogen, flow rate=200 ml/min-   Temperature conditions:    -   (1) Keeping at 20° C. for 1 minute.    -   (2) 20° C.→280° C. (Heating rate=20° C./min)    -   (3) 280° C.→20° C. (Cooling rate=20° C./min)    -   (4) 20° C.→280° C. (Heating rate=20° C./min)    -   (5) Keeping at 280° C. for 10 minute.    -   (6) 280° C.→20° C. (Cooling rate=20° C./min)    -   (7) 20° C.→280° C. (Heating rate=20° C./min)

The peak top temperature Tm³ of maximum endothermic peak observed in thefinal heating process (7) was measured.

-   Tm³≧240° C.: Dry heat resistance—very good: ⊚-   230≦Tm³<240° C.: Dry heat resistance—good: ◯-   220≦Tm³<230° C.: Dry heat resistance—medium: Δ-   Tm³<220° C.: Dry heat resistance—extremely bad: X

(6) Solvent Heat Resistance:

Polyketone was added to an aqueous zinc chloride solution comprising 65g of zinc chloride and 35 g of water, followed by stirring at 80° C. for2 hours to prepare a dope. The concentration of polyketone dissolved inthe aqueous zinc chloride solution was changed depending on theintrinsic viscosity of polyketone so that the viscosity of the dopereached 300-500 Pa·s.

Furthermore, this dope was kept at 80° C. for 24 hours, and the solutionviscosity at 80° C. of the dope before and after the keeping for 24hours was measured using B8H type viscometer (trade name) manufacturedby Tokyo Keiki Co., Ltd. When the solution viscosity just after thepreparation of the dope is shown by η₀ and the solution viscosity afterkeeping for 24 hours is shown by η₂₄, the solution viscosity increasingrate obtained by the following formula is taken as an indication of heatresistance in the solvent.

Solution viscosity increasing rate=[(η₂₄−η₀)/η₀]×100 (%)

The lower solution viscosity increasing rate means that modification ina metal salt solvent is less and solvent stability is higher.

Solution viscosity increasing rate≦30%: solvent heat resistance is verygood: ⊚

30<solution viscosity increasing rate≦50%: solvent heat resistance isgood: ◯

50<solution viscosity increasing rate≦100%: solvent heat resistance isbad: Δ

Solution viscosity increasing rate>100%: solvent heat resistance isextremely bad: X

(7) Melting Point:

The peak top temperature of the maximum endothermic peak in 100° C.→280°C. observed at the first heating process (2) in the heat resistance testof the above (5) is taken as the melting point.

(8) Measurement of Ultraviolet Spectrum:

100 milligrams of polyketone was dissolved in 100 g ofhexafluoroisopropanol (manufactured by Central Glass Co., Ltd.) and thiswas put in a quarts glass cell, followed by measuring the ultravioletspectrum using an ultraviolet visible spectrophotometer V-530(manufactured by Nihon Bunko Co., Ltd.). The measuring conditions are asfollows: scanning speed=200 nm/min, data intake interval=0.5 nm, bandwidth=2.0 nm, response=Quick, measurement range=200-600 nm, and baseline=corrected.

In the above measurement, the minimum value of absorbance observed at200-250 nm is referred to as UV_(min). The smaller UV_(min) value meansthat the amount of impurities in the polyketone is less and thermaldeterioration is less.

(9) Strength and Modulus of Fibers:

The strength-elongation of fibers was measured in accordance withJIS-L-1013.

EXAMPLE 1

25 micromoles of palladium acetate, 30 micromoles of1,3-bis{di(2-methoxyphenyl)phosphino}propane, 1 millimole of sulfuricacid and 2.5 millimoles of 1,4-benzoquinone were dissolved in 40 ml ofacetone to prepare a catalyst solution. This catalyst solution wasintroduced into a stainless steel autoclave of 2000 ml in capacity whichcontained 1000 ml of methanol-water mixed solvent (containing 12 vol %of water). Before the introduction of the catalyst, the methanol-watermixed solvent in the autoclave was previously subjected to nitrogenreplacement three times at 30° C. and 3 MPa.

After the autoclave was closed, the content was heated while stirring,and when the internal temperature reached 85° C., ethylene was addeduntil the internal pressure reached 4.5 MPa and subsequently carbonmonoxide was added until the internal pressure reached 9.0 MPa.Thereafter, a mixed gas comprising 1:1 of ethylene and carbon monoxidewas continuously fed and stirring was continued for 4 hours whilekeeping the internal pressure at 9.0 MPa and the internal temperature at85° C. After cooling, gas in the autoclave was purged and the contentwas taken out. The reaction solution was treated under the followingconditions. The resulting polyketone suspension was subjected tocentrifugal separation to prepare a wet polyketone powder containing 35wt % of liquid component. The resulting polyketone powder was washedwith 2 liters of methanol, and then again subjected to filtration andcentrifugal separation to obtain a wet polyketone powder containing 30wt % of liquid component. The powder was further washed with 2 liters ofwater at 35° C., then washed with 2 liters of methanol, and thensubjected to centrifugal separation to obtain a wet polyketone powdercontaining 25 wt % of liquid component. This wet polyketone powder wasdried at 80° C. for 4 hours under a nitrogen atmosphere to obtain 297 gof a polymer.

The measurements of ¹³C-NMR and IR revealed that the above polymer was apolyketone substantially comprising repeating units derived from carbonmonoxide and repeating units derived from ethylene. The polyketone had amelting point of 261° C. The polymerization activity was 28.0kg/g-Pd·hr, and the [η] was 6.2 dl/g. The content of Pd in thispolyketone was 5 ppm and that of P was 3 ppm. The ratio of terminalgroup A/terminal group B was 2.2. The resulting polyketone had theaverage particle diameter of 0.5 mm and a bulk density of 27 g/100 ml.

This polyketone had a UV_(min), of 0.11, a Tm³ of 241° C. and a solutionviscosity increasing rate of 32.0%, and further had good heatresistance.

EXAMPLE 2

In 4 ml of acetone were dissolved 1.25 micromole of palladium acetate,1.5 micromole of 1,3-bis(diphenylphosphino)propane and 50 micromoles ofsulfuric acid, to obtain a catalyst solution. This was dissolved in 50ml of a methanol/water mixed solvent containing 2000 ppm of water, andthis solution was introduced into a stainless steel autoclave of 100 mlin capacity which was subjected to nitrogen replacement.

Thereafter, the temperature was raised to 80° C., and ethylene wasintroduced until the internal pressure reached 4.5 MPa and subsequentlycarbon monoxide was introduced until the internal pressure reached 9.0MPa. Thereafter, a mixed gas comprising 1:1 of ethylene and carbonmonoxide was continuously fed, and polymerization was carried out for 4hours in the same formulation as in Example 1 while keeping the internalpressure at 9.0 MPa and the internal temperature at 85° C., therebyobtaining 1.33 g of a polyketone. The polymerization activity was 20.0kg/g-Pd·hr, and the [η] was 3.6 dl/g. The content of Pd in thispolyketone was 9 ppm, and the ratio of terminal group A/terminal group Bwas 7.1. This polyketone had good heat resistance.

EXAMPLE 3

The polymerization was carried out in the same manner as in Example 1,except that the composition of the catalyst solution comprised 10micromoles of palladium acetate, 12 micromoles of1,3-bis{di(2-methoxyphenyl)phosphino}propane, 1 millimole of sulfuricacid and 5.0 millimoles of 1,4-benzoquinone, and that the polymerizationtime was 10 hours, whereby 274 g of polyketone was obtained. Thepolymerization activity was 25.7 kg/g-Pd·hr, and the [η] was 6.3 dl/g.The content of Pd in this polyketone was 2 ppm, and the ratio ofterminal group A/terminal group B was 2.0. This polyketone had good heatresistance.

EXAMPLE 4

The reaction was carried out in the same manner as in Example 1, exceptthat the composition of the catalyst solution comprised 15 micromoles ofpalladium acetate, 18 micromoles of1,3-bis{di(2-methoxyphenyl)phosphino}propane, 1 millimole of sulfuricacid and 7.5 millimoles of 1,4-benzoquinone, and that before startingthe polymerization, ethylene was added until the internal pressurereached 5.0 MPa, and then carbon monoxide was added until the internalpressure reached 9.0 MPa, whereby 199 g of poyketone was obtained. Thepolymerization activity was 31.2 kg/g-Pd·hr, and the [η] was high,namely, 6.4 dl/g. The content of Pd in this polyketone was 3 ppm, andthe ratio of terminal group A/terminal group B was 1.9. This polyketonewas excellent in both of the Tm³ and solution viscosity increasing rateand had excellent heat resistance.

EXAMPLE 5

The reaction was carried out in the same manner as in Example 4, exceptthat before starting the polymerization, ethylene was added until theinternal pressure reached 5.0 MPa, and then carbon monoxide was addeduntil the internal pressure reached 7.0 MPa, followed by starting thepolymerization, whereby 153 g of poyketone was obtained. Thepolymerization activity was 24.0 kg/g-Pd·hr, and the [η] was 2.7 dl/g.The content of Pd in this polyketone was 8 ppm, and the ratio ofterminal group A/terminal group B was 1.3. This polyketone was excellentin the heat resistance.

EXAMPLE 6

The reaction was carried out in the same manner as in Example 5, exceptthat before starting the polymerization, ethylene was added until theinternal pressure reached 5.5 MPa, then carbon monoxide was added untilthe internal pressure reached 7.0 MPa, and the polymerization wasstarted, whereby 119 g of poyketone was obtained. The polymerizationactivity was 18.7 kg/g-Pd·hr, and the [η] was 2.6 dl/g. The content ofPd in this polyketone was 9 ppm, and the ratio of terminal groupA/terminal group B was 0.9. This polyketone was excellent in both of theTm³ and the solution viscosity increasing rate.

EXAMPLE 7

Into a Hastelloy autoclave of 500 ml in capacity which contained 250 mlof methanol and was subjected to nitrogen substitution were introduced20.0 ml of a catalyst solution (acetone/methanol/water=10 ml/9.9 ml/0.1ml) containing 3.125 micromoles of palladium acetate, 3.75 micromoles of1,3-bis(diphenylphosphino)propane, 50 micromoles of sulfuric acid and1.25 millimole of 1,4-benzoquinone. Thereafter, the temperature wasraised to 85° C., and a mixed gas comprising 1:1 of ethylene and carbonmonoxide was introduced so that the internal pressure reached 12 MPa,and subsequently polymerization was carried out for 2 hours in the sameformulation as in Example 1 while keeping the internal pressure at 12.0MPa and the internal temperature at 85° C. The polymerization activitywas 27.5 kg/g-Pd·hr, and the [η] was 3.2 dl/g. The content of Pd in thispolyketone was 15 ppm, and the ratio of terminal group A/terminal groupB was 7.5. This polyketone had good heat resistance.

EXAMPLE 8

The polymerization was carried out in the same manner as in Example 7,except that the polymerization pressure was 24.0 MPa. The polymerizationactivity was 40.6 kg/g-Pd·hr, and the [η] was 7.0 dl/g. The content ofPd in this polyketone was 11 ppm, and the ratio of terminal groupA/terminal group B was 2.7. This polyketone had good heat resistance.

EXAMPLE 9

The polymerization was carried out in the same manner as in Example 7,except that the polymerization solvent was isopropanol, thepolymerization temperature was 95° C., and the polymerization pressurewas 15.0 MPa. The polymerization activity was 25.0 kg/g-Pd·hr, and the[η] was 4.8 dl/g. The content of Pd in this polyketone was 18 ppm. Theterminal group A had 95% of an isopropyl ester terminal and 5% of amethyl ester terminal in the equivalent ratio, and the ratio of terminalgroup A/terminal group B was 1.9. This polyketone had good heatresistance.

EXAMPLE 10

The polymerization was carried out in the same manner as in Example 9,except that the polymerization temperature was 100° C., thepolymerization pressure was 20.0 MPa and the polymerization time was 3hours. The polymerization activity was 24.8 kg/g-Pd·hr, and the [η] was5.5 dl/g. The content of Pd in this polyketone was 13 ppm. The terminalgroup A had 97% of an isopropyl ester terminal and 3% of a methyl esterterminal in the equivalent ratio, and the ratio of terminal groupA/terminal group B was 1.6. This polyketone had good heat resistance.

EXAMPLE 11

The polymerization was carried out in the same manner as in Example 1,except that the polymerization temperature was 100° C. and thepolymerization time was 2 hours. The polymerization activity was veryhigh, namely, 61.4 kg/g-Pd·hr, and the [η] was 3.6 dl/g. The content ofPd in this polyketone was 5 ppm, and the ratio of terminal groupA/terminal group B was 5.7. This polyketone was excellent in both of theTm³ and the solution viscosity increasing rate.

EXAMPLE 12

The reaction was carried out in the same manner as in Example 1, exceptthat 500 micromoles of trifluoroacetic acid was used in place ofsulfuric acid, methanol containing 90 ppm of water was used as thepolymerization solvent, the polymerization temperature was 70° C., thepolymerization pressure was 9.0 MPa (ethylene was introduced until 3.3MPa was reached, and then a mixed gas containing ethylene:carbonmonoxide at 1:1 was introduced until 9.0 MPa was reached), and thepolymerization time was 4 hours. The polymerization activity was 12.8kg/g-Pd·hr, and the [η] was 13.9. The content of Pd in this polyketonewas 18 ppm, and the ratio of terminal group A/terminal group B was 2.4.This polyketone was excellent in both of the Tm³ and the solutionviscosity increasing rate.

EXAMPLE 13

The reaction was carried out in the same manner as in Example 1, exceptthat ethanol containing 20 vol % of water was used as the polymerizationsolvent, whereby 321 g of polyketone was obtained. The polymerizationactivity was 30.1 kg/g-Pd·hr, and the [η] was 6.5 dl/g. The content ofPd in this polyketone was 5 ppm, and that of P was 4 ppm. Only the ethylester terminal was observed in the terminal group A, and the ratio ofterminal group A/terminal group B was 2.7. This polyketone was excellentin both of the Tm³ and the solution viscosity increasing rate.

EXAMPLE 14

The polymerization was carried out in the same manner as in Example 1,except that methanesulfonic acid was used in place of sulfuric acid,naphthoquinone was used in place of benzoquinone, and methanolcontaining 0.1 vol % of water was used as the polymerization solvent,whereby 227 g of polyketone was obtained. The polymerization activitywas 21.3 kg/g-Pd·hr, and the [η] was 6.3 dl/g. The content of Pd in thispolyketone was 7 ppm, and that of P was 10 ppm. The ratio of terminalgroup A/terminal group B was 2.5. This polyketone was excellent in bothof the Tm³ and the solution viscosity increasing rate.

COMPARATIVE EXAMPLE 1

In 500 ml of acetone were dissolved 1.65 millimoles of palladiumacetate, 1.98 millimole of 1,3-bis{di(2-methoxyphenyl)phosphino}propane,33.0 millimoles of trifluoroacetic acid and 330 millimoles of1,4-benzoquinone, thereby obtaining a catalyst solution. This catalystsolution was introduced into a stainless steel autoclave of 55 liters incapacity which contained 27 liters of methanol. Before the introductionof the catalyst, the methanol in the autoclave was previously subjectedto nitrogen replacement three times at 30° C. and 3 MPa.

After the autoclave was closed, the content was heated while stirring,and when the internal temperature reached 80° C., a mixed gas comprising1:1 of ethylene and carbon monoxide was continuously fed to increase theinternal pressure to 5.5 MPa, and then stirring was continued for 1 hourwhile keeping the internal pressure at 5.5 MPa and the internaltemperature at 80° C. After cooling, gas in the autoclave was purged andthe content was taken out. The reaction solution was filtered, washedwith 36 liters of methanol, and then dried under reduced pressure toobtain 879 g of a polymer. The polymerization activity was 5.0kg/g-Pd·hr, the [η] was 4.6 dl/g, the average particle diameter was 1.5mm, and the bulk density was 21 g/100 ml.

The content of Pd and that of P in the polyketone were considerablylarge, namely, 155 ppm and 130 ppm, respectively, which were outside thescope of the present invention. In the heat resistance test, thispolyketone showed a Tm³ of 215° C. and a solution viscosity increasingrate of 105.5%, which were both extremely bad.

COMPARATIVE EXAMPLE 2

The reaction was carried out in the same manner as in ComparativeExample 1, except that the reaction time was 4 hours, to obtain 3374 gof a polymer. The polymerization activity was 4.8 kg/g-Pd·hr, and the[η] was 5.9 dl/g. The content of Pd and that of P in the polyketone wereconsiderably large, namely, 44 ppm and 30 ppm, respectively, which wereoutside the scope of the present invention. This polyketone was inferiorin both of the heat resistance and the solution viscosity increasingrate.

COMPARATIVE EXAMPLE 3

The reaction was carried out in the same manner as in ComparativeExample 2, except that methanol containing 75 vol % of water was used asthe polymerization solvent, to obtain 12.2 g of a polymer. Thepolymerization activity was 15.3 kg/g-Pd·hr. The [η] was 2.1 dl/g, whichwas insufficient.

COMPARATIVE EXAMPLE 4

The polymerization was carried out in the same manner as in Example 1,except that trifluoroacetic acid was used in place of sulfuric acid asan acid, 1,3-bis(diphenylphosphino)propane was used as the phosphorusligand, methanol was used as the polymerization solvent, thepolymerization temperature was 90° C., and the polymerization pressurewas 5.5 MPa (a mixed gas comprising 1:1 of ethylene/carbon monoxide).The polymerization activity was 10.5 kg/g-Pd·hr, and the [η] was 0.9dl/g, which was insufficient as raw materials for industrial materialsand outside the scope of the present invention. The amount of Pd in thispolyketone was 75 ppm, which was very large. The ratio of terminal groupA/terminal group B was also high, namely, 8.9, which was outside thescope of the present invention. This polyketone was conspicuously bad inthe heat resistance.

COMPARATIVE EXAMPLE 5

The reaction for 4 hours was carried out in the same manner as inExample 1, except that 50 micromoles of palladium acetate, 60 micromolesof 1,3-bis(diphenylphosphino)propane, 1 millimole of trifluoroaceticacid and 10 millimoles of 1,4-benzoquinone were dissolved in 80milliliters of acetone to prepare a catalyst solution, methanol was usedas the polymerization solvent, ethylene was introduced until theinternal pressure reached 3.5 MPa, then carbon monoxide was introduceduntil the internal pressure reached 7.0 MPa, and the reaction wasstarted and carried out under an internal pressure of 7.0 MPa and at atemperature of 90° C. As a result, 328 g of a polyketone was obtained.

The polymerization activity was 9.8 kg/g-Pd·hr, the content of Pd inthis polyketone was 21 ppm and that of P was 15 ppm, and the ratio ofterminal group A/terminal group B was 2.9. The [η] was 1.9 dl/g, whichwas insufficient and outside the scope of the present invention.

COMPARATIVE EXAMPLE 6

The reaction of 4 hours, and the washing and drying were carried out inthe same manner as in Comparative Example 2, except that 27 liters ofacetone was used as the polymerization solvent and the washing afterpolymerization was carried out with 36 liters of acetone, therebyobtaining 492 g of polyketone having a [η] of 6.7 dl/g. Thepolymerization activity was 0.7 kg/g-Pd·hr, which was utterlyinsufficient. The content of Pd and that of P in this polyketone wereconsiderably large, namely, 280 ppm and 90 ppm, respectively, which wereoutside the scope of the present invention. According to the observationby NMR, it was confirmed that this polyketone had no alkyl esterterminal group (terminal group A). This polyketone was considerably badin the heat resistance.

COMPARATIVE EXAMPLE 7

The reaction of 4 hours, and the washing and drying were carried out inthe same manner as in Comparative Example 2, except that 27 liters ofmethyl ethyl ketone containing 12 vol % of water was used as thepolymerization solvent and the washing after the polymerization wascarried out with 36 liters of methyl ethyl ketone, thereby to obtain2320 g of a polyketone having a [η] of 6.5 dl/g. The polymerizationactivity was 3.3 kg/g-Pd·hr. The content of Pd in this polyketone waslarge, namely, 45 ppm, which was outside the scope of the presentinvention. According to the observation by NMR, it was confirmed thatthis polyketone had no alkyl ester terminal group (terminal group A).This polyketone was insufficient in the heat resistance.

COMPARATIVE EXAMPLE 8

The reaction of 4 hours, and the washing and drying were carried out inthe same manner as in Comparative Example 2, except that 27 liters of1-octanol containing 12 vol % of water was used as the polymerizationsolvent, the washing after the polymerization was carried out with 36liters of 1-octanol and successively washing was carried out with 27liters of methanol, thereby to obtain a polyketone having a [η] of 7.7dl/g. The polymerization activity was 1.2 kg/g-Pd·hr. The content of Pdin this polyketone was large, namely, 138 ppm, which was outside thescope of the present invention, and the polyketone was insufficient inthe heat resistance.

COMPARATIVE EXAMPLE 9

The polymerization of 4 hours was carried out in the same formulation asof Comparative Example 4, followed by cooling. When the internaltemperature lowered to 60° C., the internal pressure was reduced to 0.3MPa and purging with nitrogen was carried out, followed by charging of500 milliliters of acetone solution containing 33 millimoles of1,3-bis{di(2-methoxyphenyl)phosphino}propane. After the charging,successively the internal temperature was raised to 110° C., followed bystirring for 15 minutes. After the termination of the stirring, coolingwas again carried out, then gas in the autoclave was purged, and thecontent was taken out. The obtained reaction mixture was subjected tofiltration, to washing of three stages, namely, washing with 5 liters ofmethanol, 3 liters of acetone and additionally 3 liters of methanol, andthen to drying under reduced pressure, thereby to obtain a polymer.

The content of Pd and that of P in this polyketone decreased to 12 ppmand 20 ppm by the after-treatment, respectively. However, the [η] was0.9, which was outside the scope of the present invention. Thispolyketone was improved in the dry heat resistance than that ofComparative Example 4, but was considerably bad in the solvent heatresistance (solution viscosity increasing rate).

COMPARATIVE EXAMPLE 10

The polymerization was carried out in the same formulation as inComparative Example 6. 10 liters of a polyketone-acetone suspensiontaken out after the completion of the reaction was washed with 20 litersof 2,4-pentanedione and filtered. Thereafter, the polymer was added to20 liters of 2,4-pentanedione, followed by subjecting to a treatment at120° C. for 6 hours with stirring, and washing with methanol and dryingunder reduced pressure to obtain a polymer.

This polyketone had a [η] of 6.7, which was nearly the same as that ofComparative Example 6, but the content of Pd and that of P decreased to9 ppm and 13 ppm by the after-treatment, respectively. However, thispolyketone had no terminal group A (namely, the ratio of terminal groupA/terminal group B being 0.0), which was outside the scope of thepresent invention. This polyketone was improved in the heat resistanceas compared with the polyketone of Comparative Example 6, but wasconsiderably bad in the solution viscosity increasing rate.

COMPARATIVE EXAMPLE 11

The polymerization was carried out in the same manner as in ComparativeExample 1, except that the polymerization pressure was 4.0 MPa and thepolymerization time was 4 hours. The polymerization activity was low,namely, 3.0 kg/g-Pd·hr, and the [η] was 5.3 dl/g, but the content of Pdwas 81 ppm, which was outside the scope of the present invention. Theratio of terminal group A/terminal group B was 4.3, and the Tm³ and thesolution viscosity increasing rate were both bad.

COMPARATIVE EXAMPLE 12

The polymerization was carried out in the same manner as in ComparativeExample 1, except that 1,3-bis(diphenylphosphino)propane was used as theligand, the polymerization temperature was 45° C., the polymerizationpressure was 5.5 MPa and the polymerization time was 22 hours. Thepolymerization activity was very low, namely, 1.0 kg/g-Pd·hr. Theresulting polyketone had a [η] of 6.3 dl/g, but the content of Pd was 43ppm, which was outside the scope of the present invention. The ratio ofterminal group A/terminal group B was 6.9, and the Tm³ and the solutionviscosity increasing rate were both considerably bad.

COMPARATIVE EXAMPLE 13

The polymerization was carried out in the same manner as in ComparativeExample 2, except that nickel acetate was used in place of palladiumacetate, 1,2-bis{di(2-methoxyphenyl)}ethane was used as the ligand, thepolymerization temperature was 85° C., the polymerization pressure was7.0 MPa (a mixed gas comprising 1:1 of ethylene/carbon monoxide) and thepolymerization time was 0.5 hour. As a result, only a trace amount ofpolyketone was obtained.

The results of the above Examples are shown in Table 1 and Table 2, andthe results of the above Comparative Examples are shown in Table 3 andTable 4. TABLE 1 Polymerization Polymerization Water PolymerizationPolymerization Catalyst temperature pressure Polymerization content timeactivity efficiency [η] ° C. MPa organic solvent (ppm) hr kg/g-Pd · hrkg/g-Pd dl/g Example 1 85 9.0 Methanol 115385 4 28.0 112.0 6.2 Example 280 9.0 Methanol 1852 4 20.0 80.0 3.6 Example 3 85 9.0 Methanol 115385 1025.7 257.0 6.3 Example 4 85 9.0 Methanol 115385 4 31.2 124.8 6.4 Example5 85 7.0 Methanol 115385 4 24.0 96.0 2.7 Example 6 85 7.0 Methanol115385 4 18.7 74.8 2.6 Example 7 85 12.0 Methanol 370 2 27.5 55.0 3.2Example 8 85 24.0 Methanol 370 2 40.6 81.2 7.0 Example 9 95 15.0Isopropanol 370 2 25.0 50.0 4.8 Example 10 100 20.0 Isopropanol 370 324.8 74.4 5.5 Example 11 100 9.0 Methanol 115385 2 61.4 122.8 3.6Example 12 70 9.0 Methanol 87 4 12.8 51.2 13.9 Example 13 85 9.0 Ethanol192308 4 30.1 120.4 6.5 Example 14 85 9.0 Methanol 3846 4 21.3 85.2 6.3

TABLE 2 Content of element Ratio of terminal Solution Evaluation of inpolymer Structure of groups Evaluation viscosity solution heat (ppm)terminal Terminal group A/ Tm₃ of heat increasing resistance UVmin Pd Pgroup A* Terminal group B ° C. resistance rate abs % Example 1 5 3 M 2.2241 ⊚ ◯ 0.11 32.0 Example 2 9 7 M 7.1 233 ◯ ◯ 0.13 44.7 Example 3 2 1 M2.0 245 ⊚ ⊚ 0.14 29.3 Example 4 3 2 M 1.9 244 ⊚ ⊚ 0.10 27.5 Example 5 85 M 1.3 242 ⊚ ◯ 0.11 34.5 Example 6 9 6 M 0.9 240 ⊚ ◯ 0.11 38.9 Example7 15 16 M 7.5 231 ◯ ◯ 0.12 47.5 Example 8 11 9 M 2.7 238 ◯ ⊚ 0.10 27.5Example 9 18 15 P 1.9 232 ◯ ⊚ 0.10 19.4 Example 10 13 12 P 1.6 235 ◯ ⊚0.10 20.1 Example 11 5 4 M 5.7 233 ◯ ◯ 0.13 39.3 Example 12 18 13 M 2.4233 ◯ ⊚ 0.11 29.3 Example 13 5 4 E 2.7 242 ⊚ ◯ 0.11 42.5 Example 15 7 10M 2.5 240 ⊚ ◯ 0.11 40.1*Structure of terminal group A: M = Methyl ester terminal, E = Ethylester terminal, P = Isopropyl ester terminal

TABLE 3 Polymerization Polymerization Polymerization WaterPolymerization Polymerization Catalyst temperature pressure organiccontent time activity efficiency [η] ° C. MPa solvent (ppm) hr kg/g-Pd ·hr kg/g-Pd dl/g Comparative 80 5.5 Methanol 0 1 5.0 5 4.6 Example 1Comparative 80 5.5 Methanol 0 4 4.8 19.2 5.9 Example 2 Comparative 859.0 Methanol 694444 4 15.3 61.2 2.1 Example 3 Comparative 90 5.5Methanol 0 1 10.5 10.5 0.9 Example 4 Comparative 85 9.0 Methanol 0 4 9.839.2 1.9 Example 5 Comparative 80 5.5 Acetone 0 4 0.7 2.8 6.7 Example 6Comparative 80 5.5 Methyl ethyl 117818 4 3.3 13.2 6.5 Example 7 ketoneComparative 80 5.5 1-Octanol 117818 4 1.2 4.8 7.7 Example 8 ComparativeMethanol 0 0.9 Example 9 Comparative Acetone 0 6.7 Example 10Comparative 80 4.0 Methanol 0 4 3.0 12.0 5.3 Example 11 Comparative 455.5 Methanol 0 22 1.0 22.0 6.3 Example 12 Comparative 85 7.0 Methanol1852 0.5 0.0 0.0 — Example 13

TABLE 4 Content of Solution element in Ratio of terminal viscositypolymer Structre of groups Evaluation increasing Evaluation of (ppm)terminal Terminal group A/ Tm₃ of heat rate solution heat UVmin Pd Pgroup A* Terminal group B ° C. resistance % resistance abs Comparative155 130 M 4.9 215 X 105.5 X 0.17 Example 1 Comparative 44 30 M 3.3 231 ◯57.1 Δ 0.15 Example 2 Comparative 15 11 M 5.6 230 ◯ 51.2 Δ 0.13 Example3 Comparative 75 66 M 8.9 211 X 125.9 X 0.14 Example 4 Comparative 21 15M 2.9 233 ◯ 60.1 Δ 0.15 Example 5 Comparative 280 90 — 0.0 n.d. X 96.5 Δ0.18 Example 6 Comparative 45 25 — 0.0 223 Δ 22.3 ⊚ 0.16 Example 7Comparative 138 120 — 0.0 n.d. X 38.5 ◯ 0.19 Example 8 Comparative 12 20M 8.9 219 X 188.0 X 0.15 Example 9 Comparative 9 5 — 0.0 235 ◯ 150.1 X0.17 Example 10 Comparative 81 55 M 4.3 213 X 77.0 Δ 0.16 Example 11Comparative 43 33 M 6.9 n.d. X 85.2 Δ 0.16 Example 12 Comparative — — —— — — — — — Example 13*Structure of terminal group A: M = Methyl ester terminal, E = Ethylester terminal, P = Isopropyl ester terminal, — = Structurecorresponding to terminal group A was not observed.n.d.: Peak was not observed.

The polyketones obtained in Examples 1-14 had the [η], content of Pdelement and terminal group ratio which are within the scope of claim ofthe present invention, and were excellent in both of the dry heatresistance and the solvent heat resistance (solution viscosityincreasing rate). On the other hand, as for the polyketones ofComparative Examples 1-13, at least one of the [η], content of Pdelement and terminal group ratio was outside the scope of the presentinvention, and these polyketones were inferior in one or both of the dryheat resistance and the solvent heat resistance (solution viscosityincreasing rate) to those of the present invention.

EXAMPLE 15

The polyketone polymerized in Example 3 was dissolved in an aqueoussolution containing 30 wt % of calcium chloride/22 wt % of zincchloride/10 wt % of lithium chloride to obtain a dope having apolyketone concentration of 6.5 wt %. The resulting dope was heated to80° C., and extruded from a spinneret having a spinneret diameter of0.15 mm φ and 250 holes into a coagulating bath comprising water of -2°C. containing 2 wt % of calcium chloride, 1.1 wt % of zinc chloride, 0.5wt % of lithium chloride and 0.1 wt % of hydrochloric acid after thedope was passed through an air gap of 10 mm. Spinnability wassatisfactory, and there occurred no troubles, such as the increase ofextrusion pressure, clogging of spinneret and breakage of filamentsduring the spinning for 6 hours.

Subsequently, the filaments were washed with a 0.1 wt % aqueoushydrochloric acid solution of 40° C. for 1 minute and furthermore withwater of 40° C. for 1 minute. Then, 0.05 wt % (based on polyketone) ofeach of IRGANOX (trademark, manufactured by Ciba Specialty ChemicalsCo., Ltd.) 1098 and IRGANOX (trademark, manufactured by Ciba SpecialtyChemicals Co., Ltd.) 1076 were applied to the filaments and then thefilaments were dried at 225° C. with fixing the length.

To the resulting dried fibers was applied an aqueous dispersion ofstearyl phosphate potassium salt, and subsequently the fibers weresubjected to four-stage stretching of 6.5 times/1.5 time/1.3 time/1.2time, namely, 15.2 times in the total, at the respective temperatures of225° C./240° C./250° C./257° C. to obtain polyketone fibers having atotal fineness of 250 dtex. The resulting fibers had a melting point of268° C., a strength of 17.5 cN/dtex, an elongation of 5.6% and a elasticmodulus of 365 cN/dtex, and thus had extremely excellent thermal andmechanical characteristics as industrial materials.

The polyketone fibers had an intrinsic viscosity of 3.7, and thecontents of metal elements remaining in the fibers were measured to findthat the content of Pd element was 2 ppm, that of Zn element was 9 ppmand that of Ca element was 8 ppm, namely, the fibers contained only asmall amount of remaining metals. Furthermore, the fibers were subjectedto Soxhlet extraction with methyl ethyl ketone at 80° C. for 4 hours toextract and remove the heat stabilizer, and then the terminal structurewas measured to find that the equivalent ratio of terminal groupA/terminal group B was 2.1.

COMPARATIVE EXAMPLE 14

The polyketone polymerized in Comparative Example 1 was subjected tospinning, washing, drying and stretching by the same methods and underthe same conditions as in Example 15. Increase of the extrusion pressureof 80% was observed during the spinning for 6 hours, and the dopeextruded from the spinneret was colored yellow after 6 hours. There wasno problem in spinnability for 3 hours after the starting of spinning,but after lapse of 3 hours, breakage of single filament was observed 8times in total. Furthermore, during the stretching process, there oftenoccurred fluffing or breakage of single filaments spun from the dopeextruded after 3 hours from the starting of spinning.

The resulting fibers had a total fineness of 260 cN/dtex, a meltingpoint of 267° C., a strength of 15.2 cN/dtex, an elongation of 5.1% anda modulus of 355 cN/dtex. The [η] of the fibers was 2.7, and as for thecontents of metal elements remaining in the fibers, the amount of Pdelement was 145 ppm, that of Zn element was 30 ppm and that of Caelement was 20 ppm, namely, they contained extremely large amounts ofmetal elements. Furthermore, when the terminal structure was measured bycarrying out the same treatment as in Example 8, the equivalent ratio ofterminal group A/terminal group B was 4.3.

COMPARATIVE EXAMPLE 14

The polyketone polymerized in Comparative Example 2 was subjected tospinning, washing, drying and stretching by the same methods and underthe same conditions as in Example 15. Clogging of spinneret or breakageof filaments was not observed during the spinning during the 6 hours,but increase of the extrusion pressure of 15% was observed during the 6hours, and the dope extruded from spinneret after the 6 hours wascolored yellow.

The resulting fibers had a total fineness of 252 cN/dtex, a meltingpoint of 268° C., a strength of 17.3 cN/dtex, an elongation of 5.6% anda modulus of 366 cN/dtex. The fibers had a [7] of 3.2, and as for thecontents of metal elements remaining in the fibers, the content of Pdelement was 40 ppm, that of Zn element was 22 ppm and that of Ca elementwas 15 ppm, namely, they contained large amounts of metal elements. Theequivalent ratio of terminal group A/terminal group B was 3.1.

COMPARATIVE EXAMPLE 16

The spinning, drying and stretching of the polyketone polymerized inComparative Example 5 were carried out in the same manner as in Example1, except that the polymer concentration was 22 wt %. The spinnabilitywas extremely inferior, and since the molecular weight was too low, thecoagulated filaments were low in the strength and the breakage of singlefilaments and cutting of filaments often occurred during taking up fromthe coagulating bath. Moreover, since cutting of filaments occurred bythe stretching at a high stretching ratio, the stretching conditionswere changed to 6 times/1.5 time/1.25 time at respective temperatures of225° C./240° C./255° C., namely, 3-stage stretching of 11.3 times intotal.

The resulting fibers had a total fineness of 1210 cN/dtex, a meltingpoint of 263° C., a strength of 8.2 cN/dtex, an elongation of 7.4% and amodulus of 159 cN/dtex, which were insufficient. The fibers had anequivalent ratio of terminal group A/terminal group B of 2.3, and as forthe contents of metal elements remaining in the fibers, the content ofPd element was 10 ppm, that of Zn element was 18 ppm and that of Caelement was 10 ppm, but the [η] was 1.2, which was utterly insufficient.

EXAMPLE 16

Six polyketone fibers produced in Example 15 were subjected to doubling,and the resulting yarn was subjected to first Z-twisting and two of theyarns were folded and subjected to final S-twisting to make a gray cord(first twist/final twist were both 390 T/m) using a ring twistermanufactured by Kaji Tekko Co., Ltd. This gray cord was immersed in anRFL solution having the following composition and thereafter wassubjected to stepwise heat treatments of 120 seconds under a tension of3 N at 160° C., 60 seconds under a tension of 4.2 N at 220° C., and 60seconds under a tension of 2.8 N at 220° C. to obtain a cord.(Composition of RFL solution) Resorcinol  22.0 parts Formalin (30 mass%)  30.0 parts Sodium hydroxide (10 mass %)  14.0 parts Water 570.0parts Vinylpyridine latex (41 mass %) 364.0 parts

The resulting polyketone cord had extremely excellent mechanicalcharacteristics and dimensional stability, namely, a tensile strength of11.8 cN/dtex, an intermediate elongation of 3.1%, and a dry heatshrinkage of 0.4%. The cords were disposed in the form of upper andlower two layers at 25 cords/inch in an unvulcanized rubber comprising70% of natural rubber, 15% of SBR and 15% of carbon black, andvulcanization was carried out at 135° C. and 35 kg/cm² for 40 minutes toobtain a belt of 8 mm thick. The belt was subjected to a flex test at100 rpm with applying a load of 10 kg. The belt was not broken even atthe test of 8 hours, and was endurable against a high load. The cordsdrawn out of the belt after being subjected to fatigue test maintained60% of the strength of the cords before the fatigue test.

Industrial Applicability

The polyketone of the present invention can be produced through ashort-time polymerization step and is obtained by a method of highproductivity without excessive washing steps. The polyketone can exhibitexcellent mechanical and thermal characteristics, such as high strength,high elastic modulus and high temperature, and is excellent in the heatresistance and solvent resistance at the time of molding, such asheating and dissolution in solvent, is hardly deteriorated duringproduction, and can provide moldings excellent in thermalcharacteristics with stable quality. The polyketone moldings of thepresent invention can be used in any forms such as fibers and films, andcan be applied to a wide variety of the uses such as clothing,reinforcing materials for rubbers, resins, cements, and optical fibers,electronic materials, battery materials, civil engineering materials,medical materials, daily commodities, fishery materials, and packagingmaterials.

1. A polyketone comprising repeating units, 95-100 mole % of which are1-oxotrimethylene represented by formula (1) and having an intrinsicviscosity of 2.5-20 dl/g, wherein the content of Pd element is 0-20 ppm,terminal structures include an alkyl ester group (terminal group A)represented by the formula (2) and an alkyl ketone group (terminal groupB) represented by formula (3), and the equivalent ratio of terminalgroup A/terminal group B is 0.1-8.0:

(wherein R¹ is hydrocarbon of 1-6 carbon atoms and R² is an organicgroup of 1-10 carbon atoms):
 2. A polyketone according to claim 1,wherein the intrinsic viscosity is 4.0-8.0 dl/g, the equivalent ratio ofterminal group A/terminal group B is 0.5-3.0, and the content of Pdelement is 0-10 ppm.
 3. A polyketone according to claim 1 or 2, whereinthe content of carboxylic acid terminal group is 0-10milli-equivalent/kg.
 4. A polyketone according to any one of claims 1-3,which has a DSC melting point Tm³ of 230° C. or higher.
 5. A polyketoneaccording to any one of claims 1-4, which has a DSC melting point Tm³ of240° C. or higher.
 6. A polyketone according to any one of claims 1-5,wherein the terminal group A is a methyl ester group represented by thefollowing formula (4), the terminal group B is an ethyl ketone grouprepresented by the following formula (5), and the equivalent ratio ofterminal group A/terminal group B is 1.0-8.0:


7. A polyketone according to any one of claims 1-5, wherein the terminalgroup A is an isopropyl ester group represented by the formula (6), theterminal group B is an ethyl ketone group represented by the formula(5), and the equivalent ratio of terminal group A/terminal group B is0.5-2.5:


8. A polyketone according to any one of claims 1-7, wherein when thepolyketone is dissolved in hexafluoroisopropanol at a concentration of0.1 wt % and ultraviolet spectrum of the solution is measured in aquarts cell at a scanning speed of 200 nm/min and a data intake intervalof 0.5 nm, the minimum value of absorbance observed at a wavelength of200-250 nm is 0.14 or less.
 9. A polyketone molded product havingrepeating units, 95-100 mol % of which are 1-oxotrimethylene representedby the formula (1) and having an intrinsic viscosity of 2.5-20 dl/g,wherein the content of Pd element is 0-20 ppm and terminal structuresinclude an alkyl ester group (terminal group A) represented by theformula (2) and an alkyl ketone group (terminal group B) represented bythe formula (3), and the equivalent ratio of terminal group A/terminalgroup B is 0.1-8.0:

(wherein R¹ is hydrocarbon of 1-6 carbon atoms and R² is an organicgroup of 1-10 carbon atoms).
 10. A polyketone fiber having repeatingunits, 95-100 mol % of which are 1-oxotrimethylene represented by theformula (1) and having an intrinsic viscosity of 2.5-20 dl/g, whereinthe content of Pd element is 0-20 ppm and the terminal structuresinclude an alkyl ester group (terminal group A) represented by theformula (2) and an alkyl ketone group (terminal group B) represented bythe formula (3), and the equivalent ratio of terminal group A/terminalgroup B is 0.1-8.0:

(wherein R¹ is hydrocarbon of 1-6 carbon atoms and R² is an organicgroup of 1-10 carbon atoms).
 11. A tire cord comprising at least 50 wt %of the polyketone fiber according to claim
 10. 12. A polyketone article,characterized in that the polyketone molded product according to claim 9or the polyketone fiber according to claim 10 is at least partly used inthe article.
 13. A polyketone article according to claim 12 which is atire, a belt or a constructional material.
 14. A fiber-reinforcedcomposite material comprising at least 1 wt % of the polyketone fiberaccording to claim 10 with respect to the whole fibers.
 15. A method forproducing a polyketone having an intrinsic viscosity of 2.5-20 dl/g bycopolymerizing carbon monoxide and an ethylenically unsaturatedcompound, wherein the copolymerization is carried out in the presence ofa metal complex catalyst obtained by reacting the following compounds(a)-(c), in the following liquid medium (d), and under the following.conditions (e): (a) a palladium compound, (b) a bidentate ligand havingan atom of Group 15 elements, (c) an acid having a pKa of 4 or less, (d)a liquid medium containing an alcohol of 1-6 carbon atoms and water andhaving a water content, as represented by the following Expression 1, of10-500,000 ppm, (e) a polymerization pressure P of 5 MPa or higher and apolymerization temperature T of 50-200° C.,$\text{Water~~~content~~~(ppm)} = {\frac{\text{Mass~~~of~~~water~~~}(g)}{\begin{matrix}\text{Volume~~~of~~~polymerization~~~solvent~~~other} \\{\text{than~~~water~~~(ml)} + \text{Volume~~~of~~~water~~~(ml)}}\end{matrix}} \times 10^{6}}$ (the volumes in the denominator of theright side are values at 25° C.).
 16. A method for producing apolyketone according to claim 15, wherein the polymerization temperatureis 70-200° C. and the polymerization pressure is 7 MPa or higher.
 17. Amethod for producing a polyketone according to claim 15 or 16, wherein(a) is at least one palladium compound selected from the groupconsisting of palladium acetate, palladium trifluoroacetate, palladiumacetylacetonate and palladium chloride; (b) is at least one phosphorusbidentate ligand selected from the group consisting of1,3-bis{di(2-methoxyphenyl)phosphino}propane,1,3-bis(diphenylphosphino)propane,1,2-bis[{di(2-methoxyphenyl)phosphino}methyl]benzene and1,3-bis{di(2-methoxy-4-sodium sulfonate-phenyl)phosphino}propane; (c) isat least one acid selected from the group consisting of sulfuric acid,methanesulfonic acid, trifluoromethanesulfonic acid and trifluoroaceticacid; and (d) is a solvent containing at least one alcohol selected fromthe group consisting of methanol, ethanol, n-propanol and isopropanol.18. A method for producing a polyketone according to any one of claims15-17, wherein the copolymerization is carried out in the presence ofbenzoquinone or naphthoquinone.
 19. A method for producing a polyketoneaccording to any one of claims 15-18, wherein the molar ratio ofethylenically unsaturated compound/carbon monoxide in the reactionvessel is 1/1-5/1.
 20. A method for producing a polyketone according toany one of claims 15-19, wherein the amount of the palladium compoundused is 0.01-10,000 micromoles per 1 liter of the polymerizationsolvent, and the amount of the bidentate legand having an atom of Group15 elements and the amount of the acid having a pKa of 4 or less are0.1-10 moles and 0.1-10,000 moles, respectively, based on 1 mole of thepalladium compound.
 21. A method for producing a polyketone according toany one of claims 15-20, wherein the content of the alcohol of 1-6carbon atoms in the liquid medium (d) is 75 vol % or more.
 22. A methodfor producing a polyketone according to any one of claims 15-21, whereinthe acid having a pKa of 4 or less is sulfuric acid and thepolymerization solvent contains an alcohol of 1-6 carbon atoms andwater, the water content being 10-500,000 ppm.
 23. A method forproducing a polyketone according to any one of claims 15-22, wherein thepolymerization pressure P (MPa) and the polymerization temperature T (°C.) satisfy both of the following Expressions 2 and 3:p≧720×exp(−0.0629×T)   Expression 2:p≧0.0179×exp(0.0607×T).   Expression 3:
 24. A method for producing apolyketone having an intrinsic viscosity of 3.0-20 dl/g bycopolymerizing carbon monoxide and an ethylenically unsaturatedcompound, wherein the polymerization activity is 10 kg/g-Pd·hr orhigher.
 25. A method for producing a polyketone having an intrinsicviscosity of 2.5-20 dl/g by copolymerizing carbon monoxide and anethylenically unsaturated compound, wherein the polymerization activityis 20 kg/g-Pd·hr or higher and the catalyst efficiency (kg/g-Pd)expressed by the product of the polymerization activity and thepolymerization time (hr) is 50 or higher.